103 research outputs found
The (not so) critical nodes of criminal networks
No full textOne of the most basic question in the analysis of social networks is to find nodes that are of particular relevance in the network. The answer that emerged in the recent literature is that the importance, or centrality, of a node x is proportional to the number of nodes that get disconnected from the network when node x is removed. We show that while in social networks such important nodes lie in their cores (i.e., maximal subgraphs in which all nodes have degree higher than a certain value), this is not necessarily the case in criminal networks. This shows that nodes whose removal affects large portions of the criminal network prefer to operate from network peripheries, thus confirming the intuition of Baker and Faulkner [4]. Our results also highlight structural differences between criminal networks and other social networks, suggesting that classical definitions of importance (or centrality) in a network fail to capture the concept of key players in criminal networks
Engineering color barcode algorithms for mobile applications
No full textThe wide availability of on-board cameras in mobile devices and the increasing demand for higher capacity have recently sparked many new color barcode designs. Unfortunately, color barcodes are much more prone to errors than black and white barcodes, due to the chromatic distortions introduced in the printing and scanning process. This is a severe limitation: the higher the expected error rate, the more redundancy is needed for error correction (in order to avoid failures in barcode reading), and thus the lower the actual capacity achieved. Motivated by this, we design, engineer and experiment algorithms for decoding color barcodes with high accuracy. Besides tackling the general trade-off between error correction and data density, we address challenges that are specific to mobile scenarios and that make the problem much more complicated in practice. In particular, correcting chromatic distortions for barcode pictures taken from phone cameras appears to be a great challenge, since pictures taken from phone cameras present a very large variation in light conditions. We propose a new barcode decoding algorithm based on graph drawing methods, which is able to run in few seconds even on low-end computer architectures and to achieve nonetheless high accuracy in the recognition phase. The main idea of our algorithm is to perform color classification using force-directed graph drawing methods: barcode elements which are very close in color will attract each other, while elements that are very far will repulse each other. © 2014 Springer International Publishing
La qualità dell’osso trabecolare valutata con il trabecular bone score (tbs) è fortemente alterata nelle osteoporosi secondarie.
No full textA Simple Method for Quantitative Assessment of Suction Drains
No full textAbstract: Suction drains are widely used in surgical practice, but a consensus is yet to be found around their use in plastic surgery. Nowadays, patients are frequently discharged from hospitals with drains still in place. Soft drains are easier to manage at home because of the reduced weight and size. The content can be disposed of when the container is full, but volume assessment is only possible when the reservoir is inflated. Evaluating the total drained volume alone is a flawed assessment method, as it might lead to erroneously decide whether a drain should be kept or removed. What we should use as a reference instead is the output quantity from the last 24 h. We can precisely determine the amount of collected material on a daily basis by closing the clip of the tubing, opening the exit valve to inflate the container, measuring and then emptying the container. However, this whole process can be complicated and put the sterile environment at risk of contamination, which is why it cannot be performed by the patient at home. We ask our patients to weigh the container daily using a kitchen scale and to write down the obtained values. When the patient returns for a postoperative checkup, they can report their measurements, thus making it easier for the surgeon to decide whether to remove the drain or not. We believe that this simple method can be safely implemented to track drains in the postoperative period after the patient is discharged. Level of Evidence V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266
The superficial vein-only DIEP flap
No full textWe read with interest this retrospective investigation by Nigro et al.,1 although we find that the conclusion is insufficiently supported. While discussing the results, the authors mention that “these values are not significantly different”; they refer to a statistical analysis by means of the t test, but do not present any P values
Determination of insect infestation on stored rice by near infrared (NIR) spectroscopy
No full textAmong grains, rice is one of the most widely consumed cereals in the world; it represents a staple food in great part of Asia and Africa, and it is also broadly diffused in America and Europe. One of the main issues of storing rice is to protect it from animal attacks; in particular, it is prone to insect infestation. Despite all the attempts made to avoid it (developing new physical barriers, traps and repellants), often food pests manage to break into granary and parcels, contaminating stored commodities. As a consequence, possible infestations must be continuously checked by producers and/or retailers. Different methods have been developed to detect insects in stored commodities, and, despite some of them demonstrated to perform well, they present the substantial limitation of being destructive. This latter characteristic undoubtedly leads to an obvious loss of product (and consequently, of profit), affecting farmers, retailers, and, finally, consumers. For this reason, the aim of the present work is to develop a methodology for the identification of insect infestation in stored rice by NIR spectroscopy coupled with discriminant and modeling classification methods. In particular, among all the different pests possibly present in granaries, the focus has been on detection of the Indian-meal moth (Plodia interpunctella), because it is considered one of the most common infesting insects. Different samples of rice, both infested and edible, coming from different farmers located in six different Countries (Cambodia, India, Italy, Pakistan, Suriname and Thailand) have been analyzed by NIR spectroscopy. Consequently, two different classification methods, Partial Least Squares Discriminant Analysis (PLS-DA) and Soft Independent Modeling of Class Analogy (SIMCA) have been applied in order to distinguish among infested and edible samples. In particular, PLS-DA allows correctly classifying 95.6% of the edible 97.5% of the contaminated samples (on the external validation set), whereas the SIMCA model, built only for the category of non-contaminated individuals, resulted highly specific (about 97%) but poorly sensitive on the test specimens. This latter approach (SIMCA) provided better predictions (in particular, in terms of sensitivity) when separate individual models were built subdividing samples in agreement with their country of origin
Authentication of “Avola almonds” by near infrared (NIR) spectroscopy and chemometrics
No full textAvola almond is part of the "Traditional Italian Agri-food Product" (PAT) list, as established by The Italian Ministry of agricultural food, forestry and tourism policies; this endorsement testifies its status as a high added value product, and, consequently, it highlights the need of analytical methodologies suitable for its authentication. For these reasons, in the present study, the possibility of developing a non-destructive approach, aimed at distinguishing almonds cultivated in the Avola area from others presenting a different geographical origin, has been investigated. To fulfil this purpose, 227 almonds, cultivated in the Avola area or in other Italian territories, have been analysed by near infrared (NIR) spectroscopy coupled with Partial Least Squares-Discriminant Analysis (PLS-DA) and Soft Independent Modelling of Class Analogies (SIMCA). The two tested approaches achieved satisfactory results (in external validation) indicating both of them would represent a suitable tool for the purpose of the study
Computing strong articulation points and strong bridges in large scale graphs
No full textLet G = (V,E) be a directed graph. A vertex v ∈ V (respectively an edge e ∈ E) is a strong articulation point (respectively a strong bridge) if its removal increases the number of strongly connected components of G. We implement and engineer the linear-time algorithms in [9] for computing all the strong articulation points and all the strong bridges of a directed graph. Our implementations are tested against real-world graphs taken from several application domains, including social networks, communication graphs, web graphs, peer2peer networks and product co-purchase graphs. The algorithms implemented turn out to be very efficient in practice, and are able to run on large scale graphs, i.e., on graphs with ten million vertices and half billion edges. Our experiments on such graphs highlight some properties of strong articulation points, which might be of independent interest
Limitations of estimating BIA-ALCL incidence risk using implant sales data and the Italian National Breast Implant Registry
No full textattempt to determine the BIA-ALCL
incidence risk (IR), however, the described methods raise
major concerns. The authors’ first aim is to provide a new
reliable method to estimate the Breast Implanted Population (BIP). To do so, they use an indirect method based on
four variables: number of Breast Implants (BI) sold/
year; purpose (aesthetic/reconstructive); number of
implanted patients stratified by purpose; time to
revision
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