196 research outputs found
Propagation of Statistical and Nuclear Data Uncertainties in Monte-Carlo Burn-up Calculations
Two methodologies to propagate the uncertainties on the nuclide inventory in combined Monte Carlo-spectrum and burn-up calculations are presented, based on sensitivity/uncertainty and random sampling techniques (uncertainty Monte Carlo method). Both enable the assessment of the impact of uncertainties in the nuclear data as well as uncertainties due to the statistical nature of the Monte Carlo neutron transport calculation. The methodologies are implemented in our MCNP–ACAB system, which combines the neutron transport code MCNP-4C and the inventory code ACAB. A high burn-up benchmark problem is used to test the MCNP–ACAB performance in inventory predictions, with no uncertainties. A good agreement is found with the results of other participants. This benchmark problem is also used to assess the impact of nuclear data uncertainties and statistical flux errors in high burn-up applications. A detailed calculation is performed to evaluate the effect of cross-section uncertainties in the inventory prediction, taking into account the temporal evolution of the neutron flux level and spectrum. Very large uncertainties are found at the unusually high burn-up of this exercise (800 MWd/kgHM). To compare the impact of the statistical errors in the calculated flux with respect to the cross uncertainties, a simplified problem is considered, taking a constant neutron flux level and spectrum. It is shown that, provided that the flux statistical deviations in the Monte Carlo transport calculation do not exceed a given value, the effect of the flux errors in the calculated isotopic inventory are negligible (even at very high burn-up) compared to the effect of the large cross-section uncertainties available at present in the data files
Understanding Charge Transfer in Donor-Acceptor/Metal Systems: A Combined Theoretical and Experimental Study
We develop an effective potential approach for assessing the flow of charge
within a two-dimensional donor-acceptor/metal network based on core-level
shifts. To do so, we perform both density functional theory (DFT) calculations
and x-ray photoemission spectroscopy (XPS) measurements of the core-level
shifts for three different monolayers adsorbed on a Ag substrate. Specifically,
we consider perfluorinated pentacene (PFP), copper phthalocyanine (CuPc) and
their 1:1 mixture (PFP+CuPc) adsorbed on Ag(111).Comment: 12 pages, 10 figure
MAC-Oriented Programmable Terahertz PHY via Graphene-based Yagi-Uda Antennas
Graphene is enabling a plethora of applications in a wide range of fields due
to its unique electrical, mechanical, and optical properties. In the realm of
wireless communications, graphene shows great promise for the implementation of
miniaturized and tunable antennas in the terahertz band. These unique
advantages open the door to new reconfigurable antenna structures which, in
turn, enable novel communication protocols at different levels of the stack.
This paper explores both aspects by, first, presenting a terahertz
Yagi-Uda-like antenna concept that achieves reconfiguration both in frequency
and beam direction simultaneously. Then, a programmable antenna controller
design is proposed to expose the reconfigurability to the PHY and MAC layers,
and several examples of its applicability are given. The performance and cost
of the proposed scheme is evaluated through full-wave simulations and
comparative analysis, demonstrating reconfigurability at nanosecond granularity
with overheads below 0.02 mm and 0.2 mW.Comment: Accepted for presentation in IEEE WCNC '1
Microsolvation of NO3 -: Structural exploration and bonding analysis
Exploration of the potential energy surfaces (PESs) of various microsolvated species associated with the microsolvation of the nitrate anion using density functional theory methods uncovers a rich and complex structural diversity previously unnoticed in the scientific literature for the [NO3(H2O)n]−, n = 1–6 clusters. Two types of interactions are at play in stabilizing the clusters: traditional water to water and charge assisted nitrate to water hydrogen bonds (HBs). The formal negative charge on oxygen atoms in nitrate strengthens hydrogen bonding among water molecules. There is outstanding agreement between available experimental data (sequential hydration enthalpies, IR spectra, and vertical detachment energies) and the corresponding expectation values obtained from our structures. Each PES is heavily populated in the vicinities of the corresponding global minimum with multiple structures contributing to the experimental properties. The last two statements, in conjunction with results from other works (see for example Phys. Chem. Chem. Phys. 2014, 16, 19241) place a warning on the generalized and naive practice of assigning experimental observations to individual structures
A wireless and portable electronic nose to differentiate musts of different ripeness degree and grape varieties
Two novel applications using a portable and wireless sensor system (e-nose) for the wine producing industry—The recognition and classification of musts coming from different grape ripening times and from different grape varieties—Are reported in this paper. These applications are very interesting because a lot of varieties of grapes produce musts with low and similar aromatic intensities so they are very difficult to distinguish using a sensory panel. Therefore the system could be used to monitor the ripening evolution of the different types of grapes and to assess some useful characteristics, such as the identification of the grape variety origin and to prediction of the wine quality. Ripening grade of collected samples have been also evaluated by classical analytical techniques, measuring physicochemical parameters, such as, pH, Brix, Total Acidity (TA) and Probable Grade Alcoholic (PGA). The measurements were carried out for two different harvests, using different red (Barbera, Petit Verdot, Tempranillo, and Touriga) and white (Malvar, Malvasía, Chenin Blanc, and Sauvignon Blanc) grape musts coming from the experimental cellar of the IMIDRA at Madrid. Principal Component Analysis (PCA) and Probabilistic Neural Networks (PNN) have been used to analyse the obtained data by e-nose. In addition, and the Canonical Correlation Analysis (CCA) method has been carried out to correlate the results obtained by both technologies. © 2015 by the authors; licensee MDPI, Basel, Switzerland.This work is being supported by the Instituto Nacional de Investigación y Tecnología
Agraria y Alimentaria (INIA) of the Economía y Competitividad Ministry, under the project
RTA2011-00095-C02-02. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer Reviewe
Terahertz Dielectric Resonator Antenna Coupled to Graphene Plasmonic Dipole
This paper presents an efficient approach for exciting a dielectric resonator
antenna (DRA) in the terahertz frequencies by means of a graphene plasmonic
dipole. Design and analysis are performed in two steps. First, the propagation
properties of hybrid plasmonic onedimensional and two-dimensional structures
are obtained by using transfer matrix theory and the finite-element method. The
coupling amount between the plasmonic graphene mode and the dielectric wave
mode is explored based on different parameters. These results, together with
DRA and plasmonic antenna theory, are then used to design a DRA antenna that
supports the mode at 2.4 THz and achieves a gain (IEEE) of up to
7 dBi and a radiation efficiency of up 70%. This gain is 6.5 dB higher than
that of the graphene dipole alone and achieved with a moderate area overhead,
demonstrating the value of the proposed structure.Comment: Accepted for presentation at EuCAP 201
Relationship between Determinants of Health, Equity, and Dimensions of Health Literacy in Patients with Cardiovascular Disease
Background: Health literacy (HL) has been linked to empowerment, use of health services, and equity. Evaluating HL in people with cardiovascular health problems would facilitate the development of suitable health strategies care and reduce inequity. Aim: To investigate the relationship between different dimensions that make up HL and social determinants in patients with cardiovascular disease. Methods: Observational, descriptive, cross-sectional study in patients with cardiovascular disease, aged 50-85 years, accessing primary care services in Valencia (Spain) in 2018-2019. The Health Literacy Questionnaire was used. Results: 252 patients. Age was significantly related with the ability to participate with healthcare providers (p = 0.043), ability to find information (p = 0.022), and understanding information correctly to know what to do (p = 0.046). Level of education was significant for all HL dimensions. Patients without studies scored lower in all dimensions. The low- versus middle-class social relationship showed significant results in all dimensions. Conclusions: In patients with cardiovascular disease, level of education and social class were social determinants associated with HL scores. Whilst interventions at individual level might address some HL deficits, inequities in access to cardiovascular care and health outcomes would remain unjustly balanced unless structural determinants of HL are taken into account
In vivo genotoxicity and inflammatory effects of uncoated and coated CeO2 NPs in mice
P17-045
Ceria nanoparticles (CeO2 NPs) have several industrial applications and pharmacological potential due to their antioxidant properties. However, toxicity data on CeO2 NPs are scarce and show contradictory results. In the present study, uncoated, polyethylene glycol- and citrate-coated CeO2 NPs (4-8 nm) were administrated to C57Bl/6 mice by repeated dose (3×) pharyngeal aspiration using four different doses of each type of NPs (corresponding to 4.4, 8.8, 17.6 and 35.2 µg Ce2+/mouse/aspiration), and sampled 1 and 28 days after the last administration. DNA damage was assessed by the comet assay locally in bronchoalveolar lavage (BAL) and lung cells, and systemically in liver cells. Micronuclei, a biomarker of chromosome damage, were analysed in bone marrow and peripheral blood erythrocytes. Immunotoxicity was evaluated by BAL cell counting. Furthermore, histopathological effects on the lungs and biodistribution of the NPs (analysis of Ce2+ in several organs) were assessed. At 24-h, a significant increase in DNA damage was induced at the highest doses by uncoated and citrate-coated NPs in BAL cells. For these NPs a significant, but non-dose-dependent, effect was observed in lung and liver cells at 28-d. No systemic genotoxic effects were observed with any of the NPs. A dose-dependent accumulation of macrophages and activated lymphocytes was seen in the lungs for all the NPs, although a milder reaction was elicited by the coated NPs. Our findings show that short-term exposure of mice to CeO2 NPs induces pulmonary inflammation, and non-dose-dependent DNA damage, but no systemic genotoxicity. (Funded by the EU FP-7 GUIDEnano, Grant Agreement No.604387)
Integrin-mediated localization of Bordetella pertussis within macrophages: role in pulmonary colonization.
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