The emergence of quantum capacitance in epitaxial graphene

We found an intrinsic redistribution of charge arises between epitaxial graphene, which has intrinsically n-type doping, and an undoped substrate. In particular, we studied in detail epitaxial graphene layers thermally elaborated on C-terminated $4H$-$SiC$ ($4H$-$SiC$ ($000{\bar{1}}$)). We have investigated the charge distribution in graphene-substrate systems using Raman spectroscopy. The influence of the substrate plasmons on the longitudinal optical phonons of the $SiC$ substrates has been detected. The associated charge redistribution reveals the formation of a capacitance between the graphene and the substrate. Thus, we give for the first time direct evidence that the excess negative charge in epitaxial monolayer graphene could be self-compensated by the $SiC$ substrate without initial doping. This induced a previously unseen redistribution of the charge-carrier density at the substrate-graphene interface. There a quantum capacitor appears, without resorting to any intentional external doping, as is fundamentally required for epitaxial graphene. Although we have determined the electric field existing inside the capacitor and revealed the presence of a minigap ($\approx 4.3meV$) for epitaxial graphene on $4H$-$SiC$ face terminated carbon, it remains small in comparison to that obtained for graphene on face terminated $Si$. The fundamental electronic properties found here in graphene on $SiC$ substrates may be important for developing the next generation of quantum technologies and electronic/plasmonic devices.Comment: 26 pages, 8 figures, available online as uncorrected proof, Journal of Materials Chemistry C (2016

Sharing data through confidential clouds: an architectural perspective

© 2015 IEEE.Cloud and mobile are two major computing paradigms that are rapidly converging. However, these models still lack a way to manage the dissemination and control of personal and business-related data. To this end, we propose a framework to control the sharing, dissemination and usage of data based on mutually agreed Data Sharing Agreements (DSAs). These agreements are enforced uniformly, and end-to-end, both on Cloud and mobile platforms, and may reflect legal, contractual or user-defined preferences. We introduce an abstraction layer that makes available the enforcement functionality across different types of nodes whilst hiding the distribution of components and platform specifics. We also discuss a set of different types of nodes that may run such a layer

Block to granular-like transition in dense bubble flows

We have experimentally investigated 2-dimensional dense bubble flows underneath inclined planes. Velocity profiles and velocity fluctuations have been measured. A broad second-order phase transition between two dynamical regimes is observed as a function of the tilt angle $\theta$. For low $\theta$ values, a block motion is observed. For high $\theta$ values, the velocity profile becomes curved and a shear velocity gradient appears in the flow.Comment: Europhys. Lett. (2003) in pres

Effects of stitching on delamination of satin weave carbon-epoxy laminates under mode I, mode II and mixed-mode I/II loadings

The objective of the present study is to characterize the effect of modified chain stitching on the delamination growth under mixed-mode I/II loading conditions. Delamination toughness under mode I is experimentally determined, for unstitched and stitched laminates, by using untabbed and tabbed double cantilever beam (TDCB) tests. The effect of the reinforcing tabs on mode I toughness is investigated. Stitching improves the energy release rate (ERR) up to 4 times in mode I. Mode II delamination toughness is evaluated in end-notched flexure (ENF) tests. Different geometries of stitched specimens are tested. Crack propagation occurs without any failure of stitching yarns. The final crack length attains the mid-span or it stops before and the specimen breaks in bending. The ERR is initially low and gradually increases with crack length to very high values. The mixedmode delamination behaviour is investigated using a mixed-mode bending (MMB) test. For unstitched specimens, a simple mixed-mode criterion is identified. For stitched specimens, stitching yarns do not break during 25% of mode I ratio tests and the ERR increase is relatively small compared to unstitched values. For 70% and 50% of mode I ratios, failures of yarns are observed during crack propagation and tests are able to capture correctly the effect of the stitching: it clearly improves the ERR for these two mixed modes, as much as threefold

Le Carcinome Mucoépidermoïde De La Parotide : Apropos De 5 Cas

Les tumeurs des glandes salivaires représentent moins de 5% de toutes les tumeurs de la tête et du cou. Parmi eux, le carcinome mucoépidermoïde est la tumeur la plus fréquente. Quarante cinq pour cent des carcinomes mucoépidermoïdes se développent au niveau de la glande parotide. Cette lésion se voit surtout chez l\'adulte vers la 5ème décade. Le diagnostic est confirmé seulement à l\'examen anatomopathologique. Son pronostic est fonction des critères histologiques.Salivary gland tumors account for less than 5% of the head and neck neoplasms. Among them, mucoepidermoid carcinoma is the most common malignant salivary gland tumor. About 45% of mucoepidermoid carcinomas occur in the parotid gland, and appear around the fifth decade of life. A certain diagnostic can be obtained only after post-operative histological examination. Histological examination indicates the patient prognosis. Journal Tunisien d\'ORL et de chirurgie cervico-faciale Vol. 16 2006: pp. 39-4

Young para-athletes display more hedonic well-being than people with disabilities not taking part in competitive sports: insights from a multi-country survey

Hedonic well-being relates to how individuals experience and rate their lives. People with disabilities due to their pathology may more frequently suffer from anxiety and depressive disorders than their able-bodied counterparts. Sports participation is an essential way to cope with disability. On the other hand, compared with their able-bodied peers, para-athletes undergo a unique series of stressors. Little is known in terms of hedonic well-being in this specific population. We present the results of a multi-country survey of self-perceived hedonic well-being by para-athletes of different sports disciplines and a control group (disabled individuals not playing competitive sports), using the "Psychological General Well-Being Index" (PGWBI). We included 1,208 participants, aged 17.39 years, 58.4% male, 41.6% female, and 70.3% para-athletes. Para-athletes exhibited higher well-being than disabled people, for all domains of the PGWBI scale. The nature of disability/impairment was significant, with those with acquired disability reporting lower well-being. Those taking part in wheelchair basketball, para-athletics, and para-swimming competitions had a higher likelihood of reporting well-being, whereas those engaged in wheelchair rugby exhibited lower well-being compared with controls. This large-scale investigation can enable a better understanding of the self-perceived hedonic well-being of disabled people

Efecto de procesos de ahumado frío y caliente y la adición de extracto polifenólico natural de Dunaliella salina sobre la calidad bioquímica y la vida útil de filetes de Sander lucioperca almacenados durante 90 días

The effects of cold and hot smoking and the addition of Dunaliella salina polyphenol extract on the biochemical quality and shelf-life of Sander lucioperca fillets after storage for 90 days at 0-4 °C were examined. The results showed a significant increase in protein, lipid, free fatty acid, and 1,1-diphenyl-2-picrylhydrazyl contents, and a decrease in peroxide and thiobarbituric acid reactive substances, and volatile base nitrogen levels in cold (CSF) and hot (HSF) smoked fillets covered with or without extract and stored for 1, 20, and 90 days compared to fresh fillets (FF). Saturated and monounsaturated fatty acids exhibited a significant increase in FF and CSF and HSF covered with or without extract. The total polyunsaturated fatty acids revealed a significant decrease in FF and CSF and HSF with or without extract. Therefore, cold and hot smoking and polyphenol extract improved the biochemical quality and storage shelf-life of fillets for 90 days at 0-4 °C.Se examinaron los efectos del ahumado en frío y en caliente y la adición de extracto de polifenoles de Dunaliella salina sobre la calidad bioquímica y la vida útil de filetes de Sander lucioperca almacenados durante 90 días a 0-4 °C. Los resultados mostraron un aumento significativo en los contenidos de proteínas, lípidos, ácidos grasos libres y 1,1-difenil-2-picrilhidrazilo, y una disminución en las sustancias reactivas de peróxido y ácido tiobarbitúrico, y los niveles de nitrógeno básico volátil en frío (LCR) y caliente (HSF) de filetes ahumados cubiertos con o sin extracto y almacenados durante 1, 20 y 90 días en comparación con los filetes frescos (FF). Los ácidos grasos saturados y monoinsaturados exhibieron un aumento significativo en FF y LCR y HSF cubiertos con o sin extracto. Los ácidos grasos poliinsaturados totales revelaron una disminución significativa en FF y CSF y HSF con o sin extracto. Por lo tanto, el ahumado en frío y en caliente y el extracto de polifenoles mejoraron la calidad bioquímica y la vida útil durante el almacenamiento de los filetes durante 90 días a 0-4 °C

Association between urban environment and mental health in Brussels, Belgium

Background Mental health disorders appear as a growing problem in urban areas. While common mental health disorders are generally linked to demographic and socioeconomic factors, little is known about the interaction with the urban environment. With growing urbanization, more and more people are exposed to environmental stressors potentially contributing to increased stress and impairing mental health. It is therefore important to identify features of the urban environment that affect the mental health of city dwellers. The aim of this study was to define associations of combined long-term exposure to air pollution, noise, surrounding green at different scales, and building morphology with several dimensions of mental health in Brussels.MethodsResearch focuses on the inhabitants of the Brussels Capital Region older than 15years. The epidemiological study was carried out based on the linkage of data from the national health interview surveys (2008 and 2013) and specifically developed indicators describing each participant's surroundings in terms of air quality, noise, surrounding green, and building morphology. These data are based on the geographical coordinates of the participant's residence and processed using Geographical Information Systems (GIS). Mental health status was approached through several validated indicators: the Symptom Checklist-90-R subscales for depressive, anxiety and sleeping disorders and the 12-Item General Health Questionnaire for general well-being. For each mental health outcome, single and multi-exposure models were performed through multivariate logistic regressions.Results Our results suggest that traffic-related air pollution (black carbon, NO2, PM10) exposure was positively associated with higher odds of depressive disorders. No association between green surrounding, noise, building morphology and mental health could be demonstrated.Conclusions These findings have important implications because most of the Brussel's population resides in areas where particulate matters concentrations are above the World Health Organization guidelines. This suggests that policies aiming to reduce traffic related-air pollution could also reduce the burden of depressive disorders in Brussels