3,238 research outputs found
Le scelte di politica economica in America Latina. Dal periodo ISI al liberismo.
nella presente tesi abbiamo affrontato le principali problematiche economiche dell'America Latina dagli anni '60 a oggi.
In Particolare ci siamo soffermati sulla discussione circa l'approccio alle politiche commerciali, concludendo con una valutazione dell'impatto di esportazioni e FDI sulla crescita
URANUS: Radio Frequency Tracking, Classification and Identification of Unmanned Aircraft Vehicles
Safety and security issues for Critical Infrastructures are growing as
attackers adopt drones as an attack vector flying in sensitive airspaces, such
as airports, military bases, city centers, and crowded places. Despite the use
of UAVs for logistics, shipping recreation activities, and commercial
applications, their usage poses severe concerns to operators due to the
violations and the invasions of the restricted airspaces. A cost-effective and
real-time framework is needed to detect the presence of drones in such cases.
In this contribution, we propose an efficient radio frequency-based detection
framework called URANUS. We leverage real-time data provided by the Radio
Frequency/Direction Finding system, and radars in order to detect, classify and
identify drones (multi-copter and fixed-wings) invading no-drone zones. We
adopt a Multilayer Perceptron neural network to identify and classify UAVs in
real-time, with % accuracy. For the tracking task, we use a Random Forest
model to predict the position of a drone with an MSE , MAE
, and . Furthermore, coordinate regression is
performed using Universal Transverse Mercator coordinates to ensure high
accuracy. Our analysis shows that URANUS is an ideal framework for identifying,
classifying, and tracking UAVs that most Critical Infrastructure operators can
adopt
Analysis of Four New Enterococcus faecalis Phages and Modeling of a Hyaluronidase Catalytic Domain from Saphexavirus
Background: Phage therapy (PT), as a method to treat bacterial infections, needs identification of bacteriophages targeting specific pathogenic host. Enterococcus faecalis, a Gram-positive coccus resident in the human gastrointestinal tract, may become pathogenic in hospitalized patients showing acquired resistance to vancomycin and thus representing a possible target for PT.
Materials and Methods: We isolated four phages that infect E. faecalis and characterized them by host range screening, transmission electron microscopy, and genome sequencing. We also identified and three-dimensional modeled a new hyaluronidase enzyme.
Results: The four phages belong to Siphoviridae family: three Efquatrovirus (namely vB_EfaS_TV51, vB_EfaS_TV54, and vB_EfaS_TV217) and one Saphexavirus (vB_EfaS_TV16). All of them are compatible with lytic cycle. vB_EfaS_TV16 moreover presents a gene encoding for a hyaluronidase enzyme.
Conclusions: The identified phages show features suggesting their useful application in PT, particularly the Saphexavirus that may be of enhanced relevance in PT because of its potential biofilm-digestion capability
Three years continuous record of the Earth’s magnetic field at Concordia Station (DomeC, Antarctica)
The magnetic observatory deployed at DomeC, Antarctica, in the French-Italian base known as Concordia hasnow been permanently running for more than three years. This paper focuses on these long-term results whichare more relevant for an observatory intended to provide absolute values of the field. The problems whichemerged in this fairly long record are discussed and solutions suggested to upgrade the observatory to the standardsof an absolute one (i.e. Intermagnet standards).Mailing address: Dr. Aude Chambodut, Ecole et Observatoiredes Sciences de la Terre 5, rue Descartes 67084, StrasbourgCedex, France; e-mail: [email protected]
MATERIALS SELECTION AND DEVELOPMENT FOR CENTRIFUGAL COMPRESSORS OPERATING IN EXTREME SOUR & ACID GAS SERVICE
TutorialThe rising demand for oil and gas has led us to exploit oil fields and gas reservoirs with increasing amounts of contaminants. Reserves of natural gas are abundant, but about 40% of the fields contain high concentrations of hydrogen sulfide, carbon dioxide, and chlorides. The harshening environment represents a challenge for the suitability of common classes of materials used for design and manufacturing of centrifugal compressor components.
According to NACE MR0175/ISO15156, a fit-for-purpose approach has been extensively used to prove the steel’s resistance in simulated field conditions and characterize the environmental limits of most martensitic and precipitation hardening stainless steels in terms of partial pressure of carbon dioxide, hydrogen sulfide, and chlorides. The literature available on the subject generally agrees that the contaminants’ concentration levels exceed the possibility of risk presented by stainless steels to turbo-machine reliability, and in worst cases to operators’ safety. Nickel-based alloys are the most robust solution to overcome the above limitations, guaranteeing high mechanical strength and resistance against stress corrosion cracking mechanisms in expected compressors’ environments.
This paper describes the advance in nickel-based alloys’ application and production of centrifugal compressors (CC) for extreme sour and acid conditions, with work that reveals the development of alternative manufacturing routes for rotor and stator components in turbomachinery. A detailed explanation of nickel-based alloys’ metallurgy, application and manufacturing capability is also given, along with recent developments of new alloys to bridge the gap between iron-base and nickel-base alloys, providing cost effective materials with enhanced corrosion resistance
Permissive role for mGlu1 metabotropic glutamate receptors in excitotoxic retinal degeneration
Neuroprotection is an unmet need in eye disorders characterized by retinal ganglion cell (RGC) death, such as prematurity-induced retinal degeneration, glaucoma, and age-related macular degeneration. In all these disorders excitotoxicity is a prominent component of neuronal damage, but clinical data discourage the development of NMDA receptor antagonists as neuroprotectants. Here, we show that activation of mGlu1 metabotropic glutamate receptors largely contributes to excitotoxic degeneration of RGCs. Mice at postnatal day 9 were challenged with a toxic dose of monosodium glutamate (MSG, 3g/kg), which caused the death of >70% of Brn-3a+ RGCs. Systemic administration of the mGlu1 receptor negative allosteric modulator (NAM), JNJ16259685 (2.5mg/kg, s.c.), was largely protective against MSG-induced RGC death. This treatment did not cause changes in motor behavior in the pups. We also injected MSG to crv4 mice, which lack mGlu1 receptors because of a recessive mutation of the gene encoding the mGlu1 receptor. MSG did not cause retinal degeneration in crv4 mice, whereas it retained its toxic activity in their wild-type littermates. These findings demonstrate that mGlu1 receptors play a key role in excitotoxic degeneration of RGCs, and encourage the study of mGlu1 receptor NAMs in models of retinal neurodegeneration
Austenitic stainless steels manufacturing by laser powder bed fusion technique
In this paper we report about the possibility to process stainless steels by laser powder bed fusion (L-PBF) systems. Austenitic stainless steels are analysed showing the possibility to successfully process them, targeting different applications. In particular, it is shown that stainless steels can be successfully processed and their mechanical behaviour allow them to be put in service. Porosities inside manufactured components are extremely low and comparable to conventionally processed materials. Mechanical performances are even higher than standard requirements. Micro surface roughness typical of the as-built material can act as crack initiator, reducing the strength in both quasi-static and dynamic conditions
Subcellular localisation of Medicago truncatula 9/13-hydroperoxide lyase reveals a new localisation pattern and activation mechanism for CYP74C enzymes
<p>Abstract</p> <p>Background</p> <p>Hydroperoxide lyase (HPL) is a key enzyme in plant oxylipin metabolism that catalyses the cleavage of polyunsaturated fatty acid hydroperoxides produced by the action of lipoxygenase (LOX) to volatile aldehydes and oxo acids. The synthesis of these volatile aldehydes is rapidly induced in plant tissues upon mechanical wounding and insect or pathogen attack. Together with their direct defence role towards different pathogens, these compounds are believed to play an important role in signalling within and between plants, and in the molecular cross-talk between plants and other organisms surrounding them. We have recently described the targeting of a seed 9-HPL to microsomes and putative lipid bodies and were interested to compare the localisation patterns of both a 13-HPL and a 9/13-HPL from <it>Medicago truncatula</it>, which were known to be expressed in leaves and roots, respectively.</p> <p>Results</p> <p>To study the subcellular localisation of plant 9/13-HPLs, a set of YFP-tagged chimeric constructs were prepared using two <it>M. truncatula </it>HPL cDNAs and the localisation of the corresponding chimeras were verified by confocal microscopy in tobacco protoplasts and leaves. Results reported here indicated a distribution of <it>M</it>.<it>truncatula </it>9/13-HPL (HPLF) between cytosol and lipid droplets (LD) whereas, as expected, <it>M</it>.<it>truncatula </it>13-HPL (HPLE) was targeted to plastids. Notably, such endocellular localisation has not yet been reported previously for any 9/13-HPL. To verify a possible physiological significance of such association, purified recombinant HPLF was used in activation experiments with purified seed lipid bodies. Our results showed that lipid bodies can fully activate HPLF.</p> <p>Conclusion</p> <p>We provide evidence for the first CYP74C enzyme, to be targeted to cytosol and LD. We also showed by sedimentation and kinetic analyses that the association with LD or lipid bodies can result in the protein conformational changes required for full activation of the enzyme. This activation mechanism, which supports previous <it>in vitro </it>work with synthetic detergent micelle, fits well with a mechanism for regulating the rate of release of volatile aldehydes that is observed soon after wounding or tissue disruption.</p
5G-MoNArch use case for ETSI ENI: elastic resource management and orchestration
Proceeding of: 2018 IEEE Conference on Standards for Communications and Networking (CSCN)5G networks will grant spectacular improvements of the most relevant Key Performance Indicators (KPIs) while allowing resource multi-tenancy through network slicing. However, the other side of the coin is represented by the huge increase of the management complexity and the need for efficient algorithms for resource orchestration. Therefore, the management and orchestration of the network through Artificial Intelligence (AI) and Machine Learning (ML) algorithms is considered a promising solution, as it allows to reduce the human interaction (usually expensive and error-prone) and scale to large scenario composed by thousands of slices in heterogeneous environments. In this paper, we provide a review of the current standardization efforts in this field, mostly due to the work performed by the Experiential Network Intelligence (ENI) industry specification group (ISG) within the European Telecommunications Standards Institute (ETSI). Then, we thoroughly describe an exemplary use case on elastic network management and orchestration through learning solutions proposed by the 5GPPP project 5G-MoNArch and recently approved at ETSI ENI
Diagnostic Accuracy of a New Antigen Test for SARS-CoV-2 Detection
Background and aims: Quick and reliable diagnostic tools play an important role in controlling the spread of the SARS-Cov-2 pandemic. The aim of this study was to evaluate the diagnostic accuracy of a new cyto-salivary antigen test aimed at detecting the presence of antigens for SARS-CoV-2, as compared by the gold standard RT-PCR and a lateral flow test. Methods: A total of 433 healthy volunteers were enrolled in the study and the sensitivity and specificity of the new cyto-salivary antigen test were calculated, as compared to the RT-PCR nasopharyngeal swab and to the lateral flow test. Results: A total of 433 samples were collected and tested at the Mediterranean Fair in Palermo from February 2021 until April 2021. The new cyto-salivary antigen had a sensitivity of 100% and a specificity of 94.2%. The sensitivity and the specificity of the lateral flow test were 55% and 100%, respectively. Conclusions: The new cyto-salivary antigen test detected more positive cases than the RT-PCR in a sample of asymptomatic subjects, demonstrating to be a promising tool for a more sensitive diagnosis of COVID-19. Further studies are warranted to better characterize its diagnostic accuracy
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