Content-based and collaborative techniques for tag recommendation: an empirical evaluation

The rapid growth of the so-called Web 2.0 has changed the surfers’ behavior. A new democratic vision emerged, in which users can actively contribute to the evolution of the Web by producing new content or enriching the existing one with user generated metadata. In this context the use of tags, keywords freely chosen by users for describing and organizing resources, spread as a model for browsing and retrieving web contents. The success of that collaborative model is justified by two factors: firstly, information is organized in a way that closely reflects the users’ mental model; secondly, the absence of a controlled vocabulary reduces the users’ learning curve and allows the use of evolving vocabularies. Since tags are handled in a purely syntactical way, annotations provided by users generate a very sparse and noisy tag space that limits the effectiveness for complex tasks. Consequently, tag recommenders, with their ability of providing users with the most suitable tags for the resources to be annotated, recently emerged as a way of speeding up the process of tag convergence. The contribution of this work is a tag recommender system implementing both a collaborative and a content-based recommendation technique. The former exploits the user and community tagging behavior for producing recommendations, while the latter exploits some heuristics to extract tags directly from the textual content of resources. Results of experiments carried out on a dataset gathered from Bibsonomy show that hybrid recommendation strategies can outperform single ones and the way of combining them matters for obtaining more accurate results.     

Regulatory Noncoding and Predicted Pathogenic Coding Variants of CCR5 Predispose to Severe COVID-19

Genome-wide association studies (GWAS) found locus 3p21.31 associated with severe COVID-19. CCR5 resides at the same locus and, given its known biological role in other infection diseases, we investigated if common noncoding and rare coding variants, affecting CCR5, can predispose to severe COVID-19. We combined single nucleotide polymorphisms (SNPs) that met the suggestive significance level (P ≤ 1 × 10⁻⁵) at the 3p21.31 locus in public GWAS datasets (6406 COVID-19 hospitalized patients and 902,088 controls) with gene expression data from 208 lung tissues, Hi-C, and Chip-seq data. Through whole exome sequencing (WES), we explored rare coding variants in 147 severe COVID-19 patients. We identified three SNPs (rs9845542, rs12639314, and rs35951367) associated with severe COVID-19 whose risk alleles correlated with low CCR5 expression in lung tissues. The rs35951367 resided in a CTFC binding site that interacts with CCR5 gene in lung tissues and was confirmed to be associated with severe COVID-19 in two independent datasets. We also identified a rare coding variant (rs34418657) associated with the risk of developing severe COVID-19. Our results suggest a biological role of CCR5 in the progression of COVID-19 as common and rare genetic variants can increase the risk of developing severe COVID-19 by affecting the functions of CCR5.     

Strain sensing fabric for hand posture and gesture monitoring.

In this paper, we report on a new technology used to implement strain sensors to be integrated in usual garments. A particular conductive mixture based on commercial products is realized and directly spread over a piece of fabric, which shows, after the treatment, piezoresistive properties, i.e., a change in resistance when it is strained. This property is exploited to realize sensorized garments such as gloves, leotards, and seat covers capable of reconstructing and monitoring body shape, posture, and gesture. In general, this technology is a good candidate for adherent wearable systems with excellent mechanical coupling with body surface. Here, we mainly focused on a sensorized glove able to detect posture and movements of the fingers. It could be used in several fields of application. We report on experimental results of a sensorized glove used as movements recorder for rehabilitation therapies and medicine. Furthermore, we describe a dedicated methodology used to read the output sensors which allowed to avoid using metallic wires for the connections. The price to be paid for all these advantages is a nonlinear electric response of the fabric sensor and a too long settling time, that in principle, make these sensors not suitable for real-time applications. Here we propose a hardware and computational solution to overcome this limitation.     

Synthesis and characterization of new polyamides and copolyamides containing 6,6'-sulfonediquinoline units

Summary Aromatic polyamides were obtained by the direct polycondensation reaction of a new monomer containing a 6,6'-sulfonediquinoline unit with various aromatic diamines. The polymers were characterised by elemental, infrared, wide angle X-ray diffraction and thermal analysis. The polyamides, possessed inherent viscosities in the range 0.24 – 0.43 dl g⁻¹, 10% weight loss in nitrogen and air above 410°C and glass transition temperatures in the range 170–220°C. The polyamides obtained by reaction with 4,4'-methylenedianiline and 4,4'-sulfonyldianiline were soluble on heating in N-methyl-2-pyrrolidinone and partially soluble in dimethylacetamide. Solubility and thermal properties of copolyamides, prepared from the reaction of 4,4'-oxydianiline with the new monomer and the 4,4'-dicarboxydiphenyl sulfone, were also studied. Received: 5 October 1998/Revised version: 19 April 1999/Accepted: 19 April 1999     

Accurate neural model identification of measurement devices

A neural approach to modeling measurement devices is presented. This approach allows the usual components of a measurement apparatus (transducers, filters, amplifiers, analog-to-digital converters, etc.) to be easily modeled by means of suitably trained artificial neural networks. Two applications regarding analog and mixed analog/digital devices are reported, highlighting the peculiarity of this approach and the accuracy that can be obtained.     

Pyrolysis of glass-hardened polyamides used in the automotive industry

Thermogravimetry and on-line flash pyrolysis–gas chromatography–mass spectrometry were used for studying thermal decomposition processes in filled polyamides deriving from used cars. The thermal decomposition of each polymer begins at about 350 °C and proceeds with a weight loss of 100% for the non-glass fibres, under nitrogen atmosphere. The analysis of the pyrolyzate compounds shows that from polyamide 66, the most abundant product volatile at degradation temperatures is cyclopentanone, while from polyamide 6 there is a considerable yield of ε-caprolactam. This revised version was published online in November 2006 with corrections to the Cover Date.     

Effect of different ventilation regimens on ewes' milk and Canestrato Pugliese cheese quality in summer

The influence of three different ventilation regimens on air pollution in sheep houses and on the quality of ewe milk and of Canestrato Pugliese cheese was investigated during the summer season. The experimental treatments were low ventilation regimen (VR=35 m3/h per ewe) split in 30-min ventilation cycles (LOV-30); moderate ventilation regimen (VR=70 m3/h per ewe) split in 30-min ventilation cycles (MOV-30); moderate ventilation regimen (VR=70 m3/h per ewe) split in 60-min ventilation cycles (MOV-60). The LOV-30 milk had higher microbial load and bulk milk somatic cell count (BMSCC) and resulted in a weaker casein matrix in the curd compared with the MOV-30 and MOV-60 treatments. At 45 d of ripening, the LOV-30 cheeses had a lower casein content and higher non-casein nitrogen (NCN) and water-soluble nitrogen (WSN) contents than the MOV-30 and MOV-60 cheeses. Urea-polyacrylamide gel electrophoresis (urea-PAGE) of the pH 4.6-soluble N extract showed that the MOV-60 cheeses had fewer bands derived from casein (CN) hydrolysis than the LOV-30 or MOV-30 cheeses, despite its having exhibited the highest plasmin (PL) activity levels. Our results suggest that the ventilation regimen is critical in dairy sheep housing for optimizing the hygienic quality of ewe milk and the proteolytic processes occurring in Canestrato Pugliese cheese during ripening.     

Structure-composition relationships of the Traditional Balsamic Vinegar close to jamming transition

The Traditional Balsamic Vinegar of Modena (TBVM), an Italian valuable specialty produced from cooked grape must becomes viscous through a long-ageing process. TBVM may undergo jamming transition which causes its depreciation. A liquid and jammed TBVM were investigated for their microstructure and elemental composition by coupling two non-destructive techniques, i.e. Environmental Scanning Electronic Microscopy (ESEM) and Energy Dispersive X-Ray Spectroscopy (EDS). The same samples were also analyzed for their molecular size distribution by Size Exclusion Chromatography (SEC) and their shear viscosity with a stress-controlled rheometer. TBVM in the jammed state behaved as a pseudoplastic fluid due to the presence of nitrogen-free polymers with a molecular size dispersion lower than a liquid TBVM, the latest showed the Newtonian flow behavior. TBVM solid particles detected close to jamming transition showed a C/O ratio of 2.5 (liquid TBVM) and 3.7 (jammed TBVM), thus much higher than the main TBVM constituents (glucose, fructose and acetic acid). The Fe and Mg content was higher and pH was lower in the jammed TBVM. It was hypothesized that jamming transition in TBVM was the result of the unbalance between two time-dependent phenomena, i.e. the increase of the bulk viscosity and the structure relaxation of nitrogen-free polymers.