A Location Privacy Extension for DVB-RCS

In this paper we studied the DVB-RCS (Return Channel through Satellite) standard from a privacy perspective and proposed an approach to incorporate a location privacy enhancing mechanism into the standard. Offering location based privacy in DVB-RCS communication is a challenge as the location of a satellite terminal must be revealed to the network operator of the DVB-RCS network for technical and administrative reasons. We proposed an approach of cloaking the location by intentionally compromising its accuracy whilst maintaining the operability and integrity of the communications system. In addition we implemented a proof of concept technique utilizing the theoretical findings of this work on a real DVB-RCS system, presenting the methodology along with the tools used and the experimental results

Airborne non-contact and contact broadband ultrasounds for frequency attenuation profile estimation of cementitious materials

[EN] In this paper, the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous cementitious materials is addressed. To accurately determine the attenuation over a wide frequency range, it is necessary to have suitable excitation techniques. We have analysed two kinds of ultrasound techniques: contact ultrasound and airborne non-contact ultrasound. The mathematical formulation for frequency-dependent attenuation has been established and it has been revealed that each technique may achieve similar results but requires specific different calibration processes. In particular, the airborne non-contact technique suffers high attenuation due to energy losses at the air-material interfaces. Thus, its bandwidth is limited to low frequencies but it does not require physical contact between transducer and specimen. In contrast, the classical contact technique can manage higher frequencies but the measurement depends on the pressure between the transducer and the specimen. Cement specimens have been tested with both techniques and frequency attenuation dependence has been estimated. Similar results were achieved at overlapping bandwidth and it has been demonstrated that the airborne non-contact ultrasound technique could be a viable alternative to the classical contact technique.The authors acknowledge the support from University College Cork (Ireland), Universidad Politecnica de Valencia and the Spanish Administration under grant BIA2014-55311-C2-2-P and Salvador Madariaga's Programme (PR2016-00344/PR2017-00658).Gosálbez Castillo, J.; Wright, W.; Jiang, W.; Carrión García, A.; Genovés, V.; Bosch Roig, I. (2018). Airborne non-contact and contact broadband ultrasounds for frequency attenuation profile estimation of cementitious materials. Ultrasonics. 88:148-156. https://doi.org/10.1016/j.ultras.2018.03.011S1481568

Ultrasonic characterization of GRC with high percentage of fly ash substitution

New applications of non-destructive techniques (NDT) with ultrasonic tests (attenuation and velocity by means of ultrasonic frequency sweeps) have been developed for the characterization of fibre-reinforced cementitious composites. According to new lines of research on glass-fibre reinforced cement (GRC) matrix modification, two similar GRC composites with high percentages of fly ash and different water/binder ratios will be studied. Conventional techniques have been used to confirm their low Ca(OH)(2) content (thermogravimetry), fibre integrity (Scanning Electron Microscopy), low porosity (Mercury Intrusion Porosimetry) and good mechanical properties (compression and four points bending test). Ultrasound frequency sweeps allowed the estimation of the attenuation and pulse velocity as functions of frequency. This ultrasonic characterization was correlated successfully with conventional techniques. (C) 2015 Elsevier B.V. All rights reserved.This work has been supported by the Government of Spain under Grant TEC2011-23403 01/01/2012Genovés Gómez, V.; Gosálbez Castillo, J.; Miralles Ricós, R.; Bonilla Salvador, MM.; Paya Bernabeu, JJ. (2015). Ultrasonic characterization of GRC with high percentage of fly ash substitution. Ultrasonics. 60:88-95. https://doi.org/10.1016/j.ultras.2015.02.016S88956

Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity

Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var. cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4). All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3 also accepts a wide range of substrates but with very strong preference for producing benzyl acetate. Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating 268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the multiplicity of AAT genes accounts for the great diversity of esters formed in melon

Acoustic emission signal processing framework to identify fracture in aluminum alloys

Acoustic emission (AE) is a common nondestructive evaluation tool that has been used to monitor fracture in materials and structures. The direct connection between AE events and their source, however, is difficult because of material, geometry and sensor contributions to the recorded signals. Moreover, the recorded AE activity is affected by several noise sources which further complicate the identification process. This article uses a combination of in situ experiments inside the scanning electron microscope to observe fracture in an aluminum alloy at the time and scale it occurs and a novel AE signal processing framework to identify characteristics that correlate with fracture events. Specifically, a signal processing method is designed to cluster AE activity based on the selection of a subset of features objectively identified by examining their correlation and variance. The identified clusters are then compared to both mechanical and in situ observed microstructural damage. Results from a set of nanoindentation tests as well as a carefully designed computational model are also presented to validate the conclusions drawn from signal processing

Childhood Visceral Leishmaniasis: Distinctive Features and Diagnosis of a Re-emerging Disease. An 11-year Experience from a Tertiary Referral Center in Athens, Greece

Background: Visceral leishmaniasis (VL) remains a public health issue in Greece. The aim of this study was to describe the clinical and epidemiologic characteristics of pediatric VL in our region as well as to evaluate the laboratory findings and the diagnostic techniques that are applied. Methods: We retrospectively reviewed the medical records of all children diagnosed with VL in an 11-year period at a tertiary public hospital in the region of Athens. Demographic features, clinical information and laboratory findings were accessed. Results: A total of 43 cases were recorded during 2005-2015. Median age of the patients was 3.7 years. Pallor (100%), fever (98%), hepatosplenomegaly (55.8%) and appetite loss (32.6%) were the most common presentations of the disease. The predominant laboratory abnormalities were anemia (100%), thrombocytopenia (90.7%), elevated inflammatory markers (86.1%) and decreased albumin/globulin (A/G) ratio (72.1%). Four patients developed secondary hemophagocytic lymphohistiocytosis syndrome, whereas in 3 others abdominal ultrasound showed splenic nodules. Bone marrow aspiration detected Leishmania parasites in 92.7% of cases and the rapid rK39 strip test indicated anti-Leishmania antibodies in 97.1% of children. In addition, all patients in whom indirect immunofluorescent antibody test was implemented had positive results. Conclusions: VL still affects children in our area. Fever, splenomegaly, anemia and appetite loss are the typical findings in children. Noninvasive techniques (immunofluorescent antibody test, rK39) in combination with bone marrow microscopy are useful in the diagnosis of pediatric VL. © 2018 Wolters Kluwer Health, Inc. All rights reserved

Laboratory- and Pilot-Scale Cultivation of <i>Tetraselmis striata</i> to Produce Valuable Metabolic Compounds

Marine microalgae are considered an important feedstock of multiple valuable metabolic compounds of high biotechnological potential. In this work, the marine microalga Tetraselmis striata was cultivated in different scaled photobioreactors (PBRs). Initially, experiments were performed using two different growth substrates (a modified F/2 and the commercial fertilizer Nutri-Leaf (30% TN—10% P—10% K)) to identify the most efficient and low-cost growth medium. These experiments took place in 4 L glass aquariums at the laboratory scale and in a 9 L vertical tubular pilot column. Enhanced biomass productivities (up to 83.2 mg L−1 d−1) and improved biomass composition (up to 41.8% d.w. proteins, 18.7% d.w. carbohydrates, 25.7% d.w. lipids and 4.2% d.w. total chlorophylls) were found when the fertilizer was used. Pilot-scale experiments were then performed using Nutri-Leaf as a growth medium in different PBRs: (a) a paddle wheel, open, raceway pond of 40 L, and (b) a disposable polyethylene (plastic) bag of 280 L working volume. Biomass growth and composition were also monitored at the pilot scale, showing that high-quality biomass can be produced, with important lipids (up to 27.6% d.w.), protein (up to 45.3% d.w.), carbohydrate (up to 15.5% d.w.) and pigment contents (up to 4.2% d.w. total chlorophylls), and high percentages of eicosapentaenoic acid (EPA). The research revealed that the strain successfully escalated in larger volumes and the biochemical composition of its biomass presents high commercial interest and could potentially be used as a feed ingredient