2,516 research outputs found

    Measuring the Temperature of a Mesoscopic Quantum Electron System by means of Single Electron Statistics

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    We measure the temperature of a mesoscopic system consisting of an ultra-dilute two dimensional electron gas at the Si/SiO2Si/SiO_2 interface in a metal-oxide-semiconductor field effect transistor (MOSFET) quantum dot by means of the capture and emission of an electron in a point defect close to the interface. Contrarily to previous reports, we show that the capture and emission by point defects in Si n-MOSFETs can be temperature dependent down to 800 mK. As the finite quantum grand canonical ensemble model applies, the time domain charge fluctuation in the defect is used to determine the temperature of the few electron gas in the channel.Comment: 4 Figures (color

    The dynamical nature of time

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    It is usually assumed that the "tt" parameter in the equations of dynamics can be identified with the indication of the pointer of a clock. Things are not so easy, however. In fact, since the equations of motion can be written in terms of tt but also of t′=f(t)t'=f(t), ff being any well behaved function, each one of those infinite parametric times t′t' is as good as the Newtonian one to study classical dynamics. Here we show that the relation between the mathematical parametric time tt in the equations of dynamics and the physical dynamical time σ\sigma that is measured with clocks is more complex and subtle than usually assumed. These two times, therefore, must be carefully distinguished since their difference may have significant consequences. Furthermore, we show that not all the dynamical clock-times are necessarily equivalent and that the observational fingerprint of this non-equivalence has the same form as that of the Pioneer anomaly.Comment: 13 pages, no figure

    Observation of electro-activated localized structures in broad area VCSELs

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    We demonstrate experimentally the electro-activation of a localized optical structure in a coherently driven broad-area vertical-cavity surface-emitting laser (VCSEL) operated below threshold. Control is achieved by electro-optically steering a writing beam through a pre-programmable switch based on a photorefractive funnel waveguide.Comment: 5 Figure

    Acute Treatment with Renal Denervation in a Patient with Resistant Hypertension and Hemorrhagic Stroke

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    A 49-year-old man with refractory hypertension was admitted to our hospital in a coma caused by hemorrhagic stroke. Severe hypertension was observed during hospitalization despite a full antihypertensive therapy. Considering the risk of enlargement of the intracranial hematoma, the decision was made to perform renal denervation (RDN). A significant blood pressure reduction was obtained after RDN. The patient had a progressive improvement of general conditions and came out of the coma after a few days. This case underlines the safety and the feasibility of RDN in a critically ill patient

    An approach based on VR to design industrial human-robot collaborative workstations

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    This paper presents an integrated approach for the design of human-robot collaborative workstations in industrial shop floors. In particular, the paper presents how to use virtual reality (VR) technologies to support designers in the creation of interactive workstation prototypes and in early validation of design outcomes. VR allows designers to consider and evaluate in advance the overall user experience, adopting a user-centered perspective. The proposed approach relies on two levels: the first allows designers to have an automatic generation and organization of the workstation physical layout in VR, starting from a conceptual description of its functionalities and required tools; the second aims at supporting designers during the design of human-machine interfaces (HMIs) by interaction mapping, HMI prototyping and testing in VR. The proposed approach has been applied on two realistic industrial case studies related to the design of an intensive warehouse and a collaborative assembly workstation for automotive industry, respectively. The two case studies demonstrate how the approach is suited for early prototyping of complex environments and human-machine interactions by taking into account the user experience from the early phases of design

    Gender differences in cyclists\u2019 crashes: an analysis of routinely recorded crash data

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    Previous research on gender differences in road crashes has focussed uniquely on car drivers and there has been little research examining such differences among cyclists. In this study, we investigated gender differences in bicycle crashes, using routinely recorded crash data. The present paper focussed on characteristics related to the type of crashes (type of collision and opponent vehicle), the infrastructure (road type and type of road segment), the environmental (season, road surface condition and weather) and time period (time of the day and day of the week). Results revealed that, compared to women cyclists, men cyclists were more likely to be involved in a crash regardless the cyclists\u2019 age. Moreover, we found gender differences in terms of type of road segment, type of opponent vehicle, type of manoeuvre of the opponent vehicle and of the cyclists, type of collision, time of the day, day of the week and season
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