336 research outputs found

    Remotely Keyed CryptoGraphics - Secure Remote Display Access Using (Mostly) Untrusted Hardware - Extended Version

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    Software that covertly monitors user actions, also known as spyware, has become a first-level security threat due to its ubiquity and the difficulty of detecting and removing it. Such software may be inadvertently installed by a user that is casually browsing the web, or may be purposely installed by an attacker or even the owner of a system. This is particularly problematic in the case of utility computing, early manifestations of which are Internet cafes and thin-client computing. Traditional trusted computing approaches offer a partial solution to this by significantly increasing the size of the trusted computing base (TCB) to include the operating system and other software. We examine the problem of protecting a user accessing specific services in such an environment. We focus on secure video broadcasts and remote desktop access when using any convenient, and often untrusted, terminal as two example applications. We posit that, at least for such applications, the TCB can be confined to a suitably modified graphics processing unit (GPU). Specifically, to prevent spyware on untrusted clients from accessing the user's data, we restrict the boundary of trust to the client's GPU by moving image decryption into GPUs. We use the GPU in order to leverage existing capabilities as opposed to designing a new component from scratch. We discuss the applicability of GPU-based decryption in these two sample scenarios and identify the limitations of the current generation of GPUs. We propose straightforward modifications to future GPUs that will allow the realization of the full approach

    Multiparametric Porous Silicon Sensors

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    We investigated the possibility of using several sensing parameters from porous silicon in order to improve gas selectivity. By fabricating porous silicon optical microcavities, three independent quantities can be measured, i.e. the electrical conductance, the photoluminescence intensity, and the wavelength of the optical resonance. We monitored the change of these three parameters as a function of NO2 (0.5-5 ppm), ethanol (300-15000 ppm) and relative humidity (0-100%). Preliminary results confirm that the examined species affect the parameters in a different way, both as a relative change and as dynamic

    Gelatin-based coating enriched with blueberry juice preserves the nutraceutical quality and reduces the microbial contamination of tomato fruit

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    To preserve quality and extend the shelf life of tomato, a bioactive edible coating was prepared using gelatin wastes from pharmaceutical industry and lyophilised blueberry juice (BJ). The effectiveness of gelatin-coating (G) and G enriched with blueberry juice (GB) was tested, monitoring carotenoids, polyphenols and flavonoids content, the antioxidant activity and the antimicrobial efficiency of coating against the native microflora. After 7 d of storage, coated fruit showed higher phenolic and flavonoids content and increased antioxidant activity, while carotenoids were unaffected by the treatments. The growth of mesophilic bacteria of GB, and the growth of coliform bacteria of G and GB were significantly reduced during the entire period. The results indicate that GB preserved the nutritional quality of tomatoes and that BJ was able to increase the antimicrobial activity of the coating. This paves the way for a possible use of this biodegradable waste polymer as an eco-friendly coating material

    Avaliação de carbono e nitrogênio em perfis de solos sob diferentes sistemas de uso da terra, em Ponta Grossa, PR.

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    Em solos agrícolas, os estoques de C e N são afetados pelo uso da terra e pelas práticas de manejo, assim como pela quantidade de resíduos aportados anualmente na superfície do solo. Sistemas agroflorestais ou integrados têm o potencial de aumentar a fertilidade do solo e o sequestro de carbono e reduzir os processos erosivos. O objetivo deste estudo foi avaliar os estoques de C e N em cinco diferentes sistemas de uso da terra, incluindo dois sistemas integrados: sistema integrado lavoura-pecuária (iLP), sistema integrado lavoura-pecuária-floresta (iLPF), plantio de Eucaliptus dunnii (E), lavoura em plantio direto (L) e campo nativo (CN). As maiores diferenças significativas entre os teores de C e N nos diferentes sistemas de uso da terra estão nas camadas até 10 cm de profundidade, embora existam pequenas diferenças nos teores de C nas camadas mais profundas

    Global gene expression analysis of Canine cutaneous mast cell tumor: Could molecular profiling be useful for subtype classification and prognostication?

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    Prognosis and therapeutic management of dogs with cutaneous mast cell tumors (MCTs) depend on clinical stage and histological grade. However, the prognostic value of this latter is still questionable. In the present study, MCT transcriptome was analyzed to identify a set of candidate genes potentially useful for predicting the biological behavior of MCTs. Fifty-one canine MCT biopsies were analyzed. Isolated and purified total RNAs were individually hybridized to the Agilent Canine V2 4x44k DNA microarray. The comparison of reference differentiated and undifferentiated MCT transcriptome revealed a total of 597 differentially expressed genes (147 down-regulated and 450 up-regulated). The functional analysis of this set of genes provided evidence that they were mainly involved in cell cycle, DNA replication, p53 signaling pathway, nucleotide excision repair and pyrimidine metabolism. Class prediction analysis identified 13 transcripts providing the greatest accuracy of class prediction and divided samples into two categories (differentiated and undifferentiated), harboring a different prognosis. The Principal Component Analysis of all samples, made by using the selected 13 markers, confirmed MCT classification. The first three components accounted for 99.924% of the total variance. This molecular classification significantly correlated with survival time (p = 0.0026). Furthermore, among all marker genes, a significant association was found between mRNA expression and MCT-related mortality for FOXM1, GSN, FEN1 and KPNA2 (p<0.05). Finally, marker genes mRNA expression was evaluated in a cohort of 22 independent samples. Data obtained enabled to identify MCT cases with different prognosis. Overall, the molecular characterization of canine MCT transcriptome allowed the identification of a set of 13 transcripts that clearly separated differentiated from undifferentiated MCTs, thus predicting outcome regardless of the histological grade. These results may have clinical relevance and warrant future validation in a prospective study

    Characterization and Testing of the Passive Magnetic Attitude Control System for the 3U AstroBio CubeSat

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    AstroBio CubeSat is a mission funded by the Italian Space Agency aimed at validating novel lab-on-chip technology, that would enable the use of micro- and nanosatellites as autonomous orbiting laboratories for research in astrobiology. This 3U CubeSat is equipped with a passive magnetic attitude control system (PMACS), including permanent magnets and hysteresis strips, which allows for stabilizing the spacecraft with the longitudinal axis in the direction of the geomagnetic field vector. This work presents the process followed for the experimental characterization of the system, performed on the engineering unit of the satellite by using a Helmholtz cage facility and a spherical air-bearing to recreate environmental conditions similar to the ones experienced during the orbital motion. The hysteresis strips are characterized starting from the determination of the hysteresis loop, from which the energy dissipation per cycle and the apparent magnetic permeability are extracted. Tests performed by using the Helmholtz cage and the air-bearing facility allows for further investigating the damping torque produced by the PMACS and validating the abovementioned parameters. Numerical analysis is then used to select the number of permanent magnets which allows for achieving a pointing accuracy within an error of 10° within 24 h from the deployment. The analysis of the flight data supports the results obtained from the experimental test campaigns, confirming the effectiveness of the proposed methods and of the PMACS design
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