215 research outputs found

    Development of an airborne ice sounding radar front-end

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    Desenvolvimento de instrumental para a padronização do volume e da forma dos incrementos de resina composta direta e relato de caso clínico

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    Objective: The objective of this work was to develop a prototype of clinical instruments that allows the standardization of the volume and shape of the composite resin mass for use in direct restorative procedures, besides a case report demonstrating the applicability of the prototype. For this, a company was selected to produce dental instruments and active in the national market with ANVISA registration. Based on a Holemback number 6 presser foot, it was geometrically reconfigured to meet the requirements for the intended design. After the development stage, this new instrument was used to report a clinical case of direct restoration of composite resin involving enamel and dentin of the occlusal-distal surfaces of the tooth 15 and occlusal of the tooth 16. The dental tissues were hybridized by the adhesive technique associated with the selective conditioning of the enamel with phosphoric acid and the application of auto-conditioning adhesive system (Clearfil SE Bond, Kuraray, Japan) in enamel and dentin. The restoration was performed with the composite resin Z350 XT (3M ESPE, USA) in colors A1 and A2B. Conclusion: The use of the prototype of auxiliary instruments in the execution of direct restorations of composite resin with the favoring to control the tensions generated by the polymerization contraction and may play an important role in the restorative training of professionals.Objetivo: O presente trabalho teve por objetivo desenvolver um protótipo de instrumental clínico que possibilita a padronização do volume e forma da massa de resina composta para o uso em procedimentos restauradores direto, além de relato de caso demonstrando a aplicabilidade do protótipo. Para isso, foi selecionada uma empresa produtora de instrumentos odontológicos e ativa no mercado nacional com registro na ANVISA. Tendo como base um calcador de Holemback número 6, esse, foi reconfigurado geometricamente afim de atingir os requisitos necessários para o desenho pretendido. Após a etapa de desenvolvimento, esse novo instrumento foi utilizado para o relato de um caso clínico de restauração direta de resina composta envolvendo esmalte e dentina das superfícies ocluso-distal do dente 15 e oclusal do dente 16. Os tecidos dentais foram hibridizados pela técnica adesiva associada de condicionamento seletivo do esmalte com ácido fosfórico e aplicação de sistema adesivo auto-condicionate (Clearfil SE Bond, Kuraray, Japão) em esmalte e dentina. A restauração foi realizada com a resina composta Z350 XT (3M ESPE, USA) nas cores A1 e A2B. Conclusão: A utilização do protótipo de instrumental auxilia na execução de restaurações direta de resina composta com o favorecimento ao controle das tensões geradas pela contração de polimerização e poderá ter papel importante no treinamento restaurador dos profissionais

    Solar-like oscillations in the G2 subgiant beta Hydri from dual-site observations

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    We have observed oscillations in the nearby G2 subgiant star beta Hyi using high-precision velocity observations obtained over more than a week with the HARPS and UCLES spectrographs. The oscillation frequencies show a regular comb structure, as expected for solar-like oscillations, but with several l=1 modes being strongly affected by avoided crossings. The data, combined with those we obtained five years earlier, allow us to identify 28 oscillation modes. By scaling the large frequency separation from the Sun, we measure the mean density of beta Hyi to an accuracy of 0.6%. The amplitudes of the oscillations are about 2.5 times solar and the mode lifetime is 2.3 d. A detailed comparison of the mixed l=1 modes with theoretical models should allow a precise estimate of the age of the star.Comment: 13 pages, 14 figures, accepted by ApJ. Fixed minor typo (ref to Fig 14

    Multisite campaign on the open cluster M67. III. Delta Scuti pulsations in the blue stragglers

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    We have made an asteroseismic analysis of the variable blue stragglers in the open cluster M67. The data set consists of photometric time series from eight sites using nine 0.6-2.1 meter telescopes with a time baseline of 43 days. In two stars, EW Cnc and EX Cnc, we detect the highest number of frequencies (41 and 26) detected in delta Scuti stars belonging to a stellar cluster, and EW Cnc has the second highest number of frequencies detected in any delta Scuti star. We have computed a grid of pulsation models that take the effects of rotation into account. The distribution of observed and theoretical frequencies show that in a wide frequency range a significant fraction of the radial and non-radial low-degree modes are excited to detectable amplitudes. Despite the large number of observed frequencies we cannot constrain the fundamental parameters of the stars. To make progress we need to identify the degrees of some of the modes either from multi-colour photometry or spectroscopy.Comment: 15 pages, 14 figs, one appendix. Part three in a series of papers describing results from an extensive multi-site campaign on the open cluster M6

    Inducing Persistent Flow Disturbances Accelerates Atherogenesis and Promotes Thin Cap Fibroatheroma Development in \u3ci\u3eD374Y\u3c/i\u3e-PCSK9 Hypercholesterolemic Minipigs

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    Background—Although disturbed flow is thought to play a central role in the development of advanced coronary atherosclerotic plaques, no causal relationship has been established. We evaluated whether inducing disturbed flow would cause the development of advanced coronary plaques, including thin cap fibroatheroma (TCFA). Methods and Results—D374Y-PCSK9 hypercholesterolemic minipigs (N=5) were instrumented with an intracoronary shear-modifying stent (SMS). Frequency-domain optical coherence tomography was obtained at baseline, immediately post-stent, 19, and 34 weeks and used to compute shear stress metrics of disturbed flow. At 34 weeks, plaque type was assessed within serially-collected histological sections and co-registered to the distribution of each shear metric. The SMS caused a flow-limiting stenosis and blood flow exiting the SMS caused regions of increased shear stress on the outer curvature and large regions of low and multidirectional shear stress on the inner curvature of the vessel. As a result, plaque burden was ~3-fold higher downstream of the SMS compared to both upstream of the SMS and in the control artery (pppp\u3c0.005). Conclusions—These data support a causal role for lowered and multidirectional shear stress in the initiation of advanced coronary atherosclerotic plaques. Persistently lowered shear stress appears to be the principal flow disturbance needed for the formation of TCFA

    Multi-site campaign on the open cluster M67. I. Observations and photometric reductions

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    We report on an ambitious multi-site campaign aimed at detecting stellar variability, particularly solar-like oscillations, in the red giant stars in the open cluster M67 (NGC 2682). During the six-week observing run, which comprised 164 telescope nights, we used nine 0.6-m to 2.1-m class telescopes located around the world to obtain uninterrupted time-series photometry. We outline here the data acquisition and reduction, with emphasis on the optimisation of the signal-to-noise of the low amplitude (50-500 micromag) solar-like oscillations. This includes a new and efficient method for obtaining the linearity profile of the CCD response at ultra high precision (~10 parts per million). The noise in the final time series is 0.50 mmag per minute integration for the best site, while the noise in the Fourier spectrum of all sites combined is 20 micromag. In addition to the red giant stars, this data set proves to be very valuable for studying high-amplitude variable stars such as eclipsing binaries, W UMa systems and delta Scuti stars.Comment: 12 pages, 13 figures, accepted by MNRA

    Self-Assemblage and Quorum in the Earthworm Eisenia fetida (Oligochaete, Lumbricidae)

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    Despite their ubiquity and ecological significance in temperate ecosystems, the behavioural ecology of earthworms is not well described. This study examines the mechanisms that govern aggregation behaviour specially the tendency of individuals to leave or join groups in the compost earthworm Eisenia fetida, a species with considerable economic importance, especially in waste management applications. Through behavioural assays combined with mathematical modelling, we provide the first evidence of self-assembled social structures in earthworms and describe key mechanisms involved in cluster formation. We found that the probability of an individual joining a group increased with group size, while the probability of leaving decreased. Moreover, attraction to groups located at a distance was observed, suggesting a role for volatile cues in cluster formation. The size of earthworm clusters appears to be a key factor determining the stability of the group. These findings enhance our understanding of intra-specific interactions in earthworms and have potential implications for extraction and collection of earthworms in vermicomposting processes
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