1,027 research outputs found

    Order-by-disorder in classical oscillator systems

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    We consider classical nonlinear oscillators on hexagonal lattices. When the coupling between the elements is repulsive, we observe coexisting states, each one with its own basin of attraction. These states differ by their degree of synchronization and by patterns of phase-locked motion. When disorder is introduced into the system by additive or multiplicative Gaussian noise, we observe a non-monotonic dependence of the degree of order in the system as a function of the noise intensity: intervals of noise intensity with low synchronization between the oscillators alternate with intervals where more oscillators are synchronized. In the latter case, noise induces a higher degree of order in the sense of a larger number of nearly coinciding phases. This order-by-disorder effect is reminiscent to the analogous phenomenon known from spin systems. Surprisingly, this non-monotonic evolution of the degree of order is found not only for a single interval of intermediate noise strength, but repeatedly as a function of increasing noise intensity. We observe noise-driven migration of oscillator phases in a rough potential landscape.Comment: 12 pages, 13 figures; comments are welcom

    Information fusion of GNSS sensor readings, field notes, and expert's a priori knowledge

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    Documenting machinery movements by using positioning technologies, such as global navigation satellite systems (GNSS), is essential to understand and further improve construction processes. However, before measurements can be meaningfully analysed the documented movements should be filtered to exclude outliers. Eliminating outliers manually is a time-demanding process, while automatic filtering can be inaccurate. In particular, path elements may get lost if machine-specific movements are misconceived as noisy data. As a trade-off, we propose an information fusion approach to filter paths of construction machines in a semi-automatic way. The approach allows an expert to relate “hard” sensor and “soft” field records with his or her expectations about how machines can move in real construction projects. Specially developed open-source software illustrates the proposed approach for filtering the documented paths of machines involved in road paving projects. The initial testing of the developed software showed its suitability to filter outliers in GNSS data and identified possibilities for further improvements

    Elaboration and characterization of the electrodeposited phosphates masses doped with various ions on stainless steel

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    The present paper is focused on elaboration of phosphate masses with good molar ratios on SS 316L, with fluoride, Zn2+ and Cu2+ as dopant ions, using an electrochemical procedure and also the attempt to select the best conditions for stainless steel. The surface was characterized using X-ray difraction, AFM and contact angle measurements. X-ray has evidenced crystaline phases, contact angle measurements has established the balance hydrophyl-hydrophob and AFM established roughness values. The inductively coupled spectrometry (ICP-MS) has quantified the amount of cooper and zinc ions released. In order to be used in biomedical applications hemolysis and antibacterial tests have been performed.Fil: Totea, G.. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Ionita, D.. Faculty of Applied Chemistry and Materials Science; RumaniaFil: Katunar, Maria Rosa. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Mar del Plata. Instituto de InvestigaciĂłn En Ciencia y TecnologĂ­a de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de IngenierĂ­a; ArgentinaFil: Cere, Silvia. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Mar del Plata. Instituto de InvestigaciĂłn En Ciencia y TecnologĂ­a de Materiales (i); Argentina. Universidad Nacional de Mar del Plata. Facultad de IngenierĂ­a; ArgentinaFil: Demetrescu, I.. Faculty of Applied Chemistry and Materials Science; Rumani

    Antibacterial nanocomposites based on Ag NPs and HMDSO deposited by atmospheric pressure plasma

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    The development of new multifunctional coatings with antimicrobial properties has a special interest in several applications for pharmaceutical and medical products. This work reports on the deposition of antimicrobial coatings based on silver nanoparticles (Ag NPs) embedded in an organosilicon film onto woven and nonwoven textiles. The Ag nanoparticles admixed with hexamethyldisiloxane (HMDSO) vapours are introduced by means of an atomizer system in the remote discharge of an atmospheric pressure plasma source operating in argon. The chemical properties and the surface morphology of the coatings with antimicrobial potential are discussed.This work was performed within the M-ERA-NET project PlasmaTex, contract 31/2016/ UEFISCDI. The financial support from the Ministry of Research and Innovation under the Nucleus contract 4N/2016 is gratefully acknowledged.info:eu-repo/semantics/publishedVersio

    Identification of Rare Causal Variants in Sequence-Based Studies: Methods and Applications to VPS13B, a Gene Involved in Cohen Syndrome and Autism

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    Pinpointing the small number of causal variants among the abundant naturally occurring genetic variation is a difficult challenge, but a crucial one for understanding precise molecular mechanisms of disease and follow-up functional studies. We propose and investigate two complementary statistical approaches for identification of rare causal variants in sequencing studies: a backward elimination procedure based on groupwise association tests, and a hierarchical approach that can integrate sequencing data with diverse functional and evolutionary conservation annotations for individual variants. Using simulations, we show that incorporation of multiple bioinformatic predictors of deleteriousness, such as PolyPhen-2, SIFT and GERP++ scores, can improve the power to discover truly causal variants. As proof of principle, we apply the proposed methods to VPS13B, a gene mutated in the rare neurodevelopmental disorder called Cohen syndrome, and recently reported with recessive variants in autism. We identify a small set of promising candidates for causal variants, including two loss-of-function variants and a rare, homozygous probably-damaging variant that could contribute to autism risk

    Recycling bins, garbage cans or think tanks? Three myths regarding policy analysis institutes

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    The phrase 'think tank' has become ubiquitous – overworked and underspecified – in the political lexicon. It is entrenched in scholarly discussions of public policy as well as in the 'policy wonk' of journalists, lobbyists and spin-doctors. This does not mean that there is an agreed definition of think tank or consensual understanding of their roles and functions. Nevertheless, the majority of organizations with this label undertake policy research of some kind. The idea of think tanks as a research communication 'bridge' presupposes that there are discernible boundaries between (social) science and policy. This paper will investigate some of these boundaries. The frontiers are not only organizational and legal; they also exist in how the 'public interest' is conceived by these bodies and their financiers. Moreover, the social interactions and exchanges involved in 'bridging', themselves muddy the conception of 'boundary', allowing for analysis to go beyond the dualism imposed in seeing science on one side of the bridge, and the state on the other, to address the complex relations between experts and public policy
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