67,343 research outputs found

    Coding with Scrambling, Concatenation, and HARQ for the AWGN Wire-Tap Channel: A Security Gap Analysis

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    This study examines the use of nonsystematic channel codes to obtain secure transmissions over the additive white Gaussian noise (AWGN) wire-tap channel. Unlike the previous approaches, we propose to implement nonsystematic coded transmission by scrambling the information bits, and characterize the bit error rate of scrambled transmissions through theoretical arguments and numerical simulations. We have focused on some examples of Bose-Chaudhuri-Hocquenghem (BCH) and low-density parity-check (LDPC) codes to estimate the security gap, which we have used as a measure of physical layer security, in addition to the bit error rate. Based on a number of numerical examples, we found that such a transmission technique can outperform alternative solutions. In fact, when an eavesdropper (Eve) has a worse channel than the authorized user (Bob), the security gap required to reach a given level of security is very small. The amount of degradation of Eve's channel with respect to Bob's that is needed to achieve sufficient security can be further reduced by implementing scrambling and descrambling operations on blocks of frames, rather than on single frames. While Eve's channel has a quality equal to or better than that of Bob's channel, we have shown that the use of a hybrid automatic repeat-request (HARQ) protocol with authentication still allows achieving a sufficient level of security. Finally, the secrecy performance of some practical schemes has also been measured in terms of the equivocation rate about the message at the eavesdropper and compared with that of ideal codes.Comment: 29 pages, 10 figure

    Metastable Features of Economic Networks and Responses to Exogenous Shocks

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    It has been proved that network structure plays an important role in addressing a collective behaviour. In this paper we consider a network of firms and corporations and study its metastable features in an Ising based model. In our model, we observe that if in a recession the government imposes a demand shock to stimulate the network, metastable features shape its response. Actually we find that there is a minimum bound where demand shocks with a size below it are unable to trigger the market out from recession. We then investigate the impact of network characteristics on this minimum bound. We surprisingly observe that in a Watts-Strogatz network though the minimum bound depends on the average of the degrees, when translated into the economics language, such a bound is independent of the average degrees. This bound is about 0.44Δ0.44 \DeltaGDP, where Δ\DeltaGDP is the gap of GDP between recession and expansion. We examine our suggestions for the cases of the United States and the European Union in the recent recession, and compare them with the imposed stimulations. While stimulation in the US has been above our threshold, in the EU it has been far below our threshold. Beside providing a minimum bound for a successful stimulation, our study on the metastable features suggests that in the time of crisis there is a "golden time passage" in which the minimum bound for successful stimulation can be much lower. So, our study strongly suggests stimulations to be started within this time passage.Comment: 13 pages, 10 figures, accepted for publication in PloS On

    Development and validation of a GC-MS method for the detection and quantification of clotiapine in blood and urine specimens and application to a postmortem case

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    INTRODUCTION: Clotiapine is an atypical antipsychotic of the dibenzothiazepine class introduced in a few European countries since 1970, efficient in treatment-resistant schizophrenic patients. There is little published data on the therapeutic and toxic concentrations of this drug. AIMS: The aim of the present study is the development and validation of a method that allows the detection and quantification of clotiapine in blood and urine specimens by gas chromatography-mass spectrometry (GC-MS). METHODS: Validation was performed working on spiked postmortem blood and urine samples. Samples were extracted with liquid-liquid extraction (LLE) technique at pH 8.5 with n-hexane/dichloromethane (85/15 v/v) and analysis was followed by GC-MS. Methadone-d9 was used as internal standard. RESULTS: The limit of detection (LOD) was 1.2 and 1.3 ng/mL for urine and blood, respectively, while the lower limit of quantification (LLOQ) was 3.9 and 4.3 ng/mL, respectively. Linearity, precision, selectivity, accuracy, and recovery were also determined. The method was applied to a postmortem case. The blood and urine clotiapine concentrations were 1.32 and 0.49 μg/mL, respectively. CONCLUSIONS: A reliable GC-MS method for the detection and quantification of clotiapine in blood and urine samples has been developed and fully validated and then applied to a postmortem case

    Compact QC-LDPC Block and SC-LDPC Convolutional Codes for Low-Latency Communications

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    Low decoding latency and complexity are two important requirements of channel codes used in many applications, like machine-to-machine communications. In this paper, we show how these requirements can be fulfilled by using some special quasi-cyclic low-density parity-check block codes and spatially coupled low-density parity-check convolutional codes that we denote as compact. They are defined by parity-check matrices designed according to a recent approach based on sequentially multiplied columns. This method allows obtaining codes with girth up to 12. Many numerical examples of practical codes are provided.Comment: 5 pages, 1 figure, presented at IEEE PIMRC 201

    Use of Medicinal Cannabis and Synthetic Cannabinoids in Posttraumatic Stress Disorder (PTSD): a systematic review

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    Background and Objectives: Post-traumatic stress disorder (PTSD) is a common psychiatric disorder resulting from a traumatic event, is manifested through hyperarousal, anxiety, depressive symptoms, and sleep disturbances. Despite several therapeutic approaches being available, both pharmacological and psychological, recently a growing interest has developed in using cannabis and synthetic cannabinoids stems from their consideration as more efficient and better tolerated alternatives for the treatment of this condition. The present paper aims to evaluate the clinical and therapeutic potentials of medical cannabis and synthetic cannabinoids in treating PTSD patients. Methods: A systematic electronic search was performed, including all papers published up to May 2019, using the following keywords (((cannabis[Title/Abstract]) OR (synthetic cannabinoids [Title/Abstract])) AND ((PTSD[Title/Abstract]) OR (Posttraumatic stress disorder[Title/Abstract]))) for the topics ‘Cannabis’, ‘Synthetic Cannabinoids’, ‘PTSD’, and MESH terms, on the PubMed, Cochrane Library, and Web of Science online databases. For data gathering purposes, PRISMA guidelines were followed. Results were organized into two groups, considering cannabis and synthetic cannabinoids as different therapeutic approaches for PTSD. Results: Present data show that cannabis and synthetic cannabinoids, both acting on the endocannabinoids system, may have a potential therapeutic use for improving PTSD symptoms, e.g., reducing anxiety, modulating memory-related processes, and improving sleep. Conclusions: Even though the current literature suggests that cannabis and synthetic cannabinoids may have a role in the treatment of PTSD, there is currently limited evidence regarding their safety and efficacy. Therefore, additional research is needed in order to better understand the effectiveness and therapeutic usage of these drug classes and monitor their safety.Peer reviewe

    High-grade vaginal intraepithelial neoplasia and risk of progression to vaginal cancer. a multicentre study of the Italian Society of Colposcopy and Cervico-Vaginal Pathology (SICPCV)

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    OBJECTIVE: The aim of this study was to analyse the women with high grade vaginal intraepithelial neoplasia (HG-VaIN), in order to identify a subset of women at higher risk of progression to invasive vaginal cancer. MATERIALS AND METHODS: The medical records of all the women diagnosed with HG-VaIN, and subsequently treated, from January 1995 to December 2013 were analyzed in a multicentre retrospective case series. The rate of progression to invasive vaginal cancer and the potential risk factors were evaluated. RESULTS: 205 women with biopsy diagnosis of HG-VaIN were considered, with a mean follow up of 57 months (range 4-254 months). 12 cases of progression to vaginal squamocellular cancer were observed (5.8%), with a mean time interval from treatment to progression of 54.6 months (range 4-146 months). The rate of progression was significantly higher in women diagnosed with VaIN3 compared with VaIN2 (15.4% vs. 1.4%, p < 0.0001). Women with HG-VaIN and with previous hysterectomy showed a significantly higher rate of progression to invasive vaginal cancer compared to non-hysterectomised women (16.7% vs. 1.4%, p < 0.0001). A higher risk of progression for women with VaIN3 and for women with previous hysterectomy for cervical HPV-related disease was confirmed by multivariable logistic regression analysis. CONCLUSIONS: A higher rate of progression to vaginal cancer was reported in women diagnosed with VaIN3 on biopsy and in women with previous hysterectomy for HPV-related cervical disease. These patients should be considered at higher risk, thus a long lasting and accurate follow up is recommended

    Multiple solutions for a fractional pp-Laplacian equation with sign-changing potential

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    We use a variant of the fountain Theorem to prove the existence of infinitely many weak solutions for the following fractional p-Laplace equation (-\Delta)^{s}_{p}u+V(x)|u|^{p-2}u=f(x,u) in R^N, where s(0,1)s \in (0,1),p2 p \geq 2,N2 N \geq 2, (Δ)ps(-\Delta)^{s}_{p} is the fractional pp-Laplace operator, the nonlinearity f is pp-superlinear at infinity and the potential V(x) is allowed to be sign-changing

    The “abuse of right” in EU company law and EU tax law: A re-reading of the ECJ case-law and the quest for a unitary notion

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    This article discusses whether, in light of the developments of the ECJ case-law in different areas, and in particular in the areas of EU company law and EU tax law, it is possible to identify a unitary concept of “abuse of rights” in EU law, and whether the prohibition of abuse of right based on such concept has reached the status of “general principle” of EU law. Through a re-reading of the ECJ case-law, it is argued that it is possible to identify a unitary concept of abuse of rights, and that the prohibition of abuse of rights could be described in terms of a “general principle with a sui generis aspect”, which general principle, in the author’s view, should be seen as complementary to the prohibition of abuse of rights spelt out in Art. 54 of the Charter of Fundamental Rights for consistency of the (post-Lisbon Treaty) EU legal order

    On a diffusion model with absorption and production

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    We discuss the structure of radial solutions of some superlinear elliptic equations which model diffusion phenomena when both absorption and production are present. We focus our attention on solutions defined in R (regular) or in R \ {0} (singular) which are infinitesimal at infinity, discussing also their asymptotic behavior. The phenomena we find are present only if absorption and production coexist, i.e., if the reaction term changes sign. Our results are then generalized to include the case where Hardy potentials are considered

    The Hierarchic treatment of marine ecological information from spatial networks of benthic platforms

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    Measuring biodiversity simultaneously in different locations, at different temporal scales, and over wide spatial scales is of strategic importance for the improvement of our understanding of the functioning of marine ecosystems and for the conservation of their biodiversity. Monitoring networks of cabled observatories, along with other docked autonomous systems (e.g., Remotely Operated Vehicles [ROVs], Autonomous Underwater Vehicles [AUVs], and crawlers), are being conceived and established at a spatial scale capable of tracking energy fluxes across benthic and pelagic compartments, as well as across geographic ecotones. At the same time, optoacoustic imaging is sustaining an unprecedented expansion in marine ecological monitoring, enabling the acquisition of new biological and environmental data at an appropriate spatiotemporal scale. At this stage, one of the main problems for an effective application of these technologies is the processing, storage, and treatment of the acquired complex ecological information. Here, we provide a conceptual overview on the technological developments in the multiparametric generation, storage, and automated hierarchic treatment of biological and environmental information required to capture the spatiotemporal complexity of a marine ecosystem. In doing so, we present a pipeline of ecological data acquisition and processing in different steps and prone to automation. We also give an example of population biomass, community richness and biodiversity data computation (as indicators for ecosystem functionality) with an Internet Operated Vehicle (a mobile crawler). Finally, we discuss the software requirements for that automated data processing at the level of cyber-infrastructures with sensor calibration and control, data banking, and ingestion into large data portals.Peer ReviewedPostprint (published version
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