290 research outputs found

    Size scaling of the addition spectra in silicon quantum dots

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    We investigate small artificial quantum dots obtained by geometrically controlled resistive confinement in low mobility silicon-on-insulator nanowires. Addition spectra were recorded at low temperature for various dot areas fixed by lithography. We compare the standard deviation of the addition spectra with theory in the high electron concentration regime. We find that the standard deviation scales as the inverse area of the dot and its absolute value is comparable to the energy spacing of the one particle spectrum.Comment: 4 pages, 5 figure

    Management of malignant pleural mesothelioma: a French multicenter retrospective study (GFPC 0802 study)

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    BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare disease with poor prognosis in spite of significant improvement in survival, due to new chemotherapy regimens. We describe here patients’ profiles and management in daily practice in France. METHODS: Observational retrospective study. Data were collected from medical files. All patients with histologically proven MPM diagnosed from January 2005 to December 2008 were included in the participating sites. RESULTS: Four hundred and six patients were included in 37 sites: mean age 68.9 ± 9.8 years, male predominance (sex ratio 3.27), latency of the disease 45.7 years, epithelioïd type 83 %. Diagnosis was made using thoracoscopy in 80.8 % of patients. Radical surgery was performed in 6.2 % of cases. Chemotherapy was administered to 74.6 % of patients. First line regimens consisted mainly of platinum + pemetrexed (91 %) or pemetrexed alone (7 %). Objective response rate was 17.2 % and another 41.6 % of patients experienced disease stabilization. Half of these patients underwent second line chemotherapy (platinium + pemetrexed 31.6 %, pemetrexed alone 24.6 %), resulting in a 6 % response rate. Third-line chemotherapy (56 patients) yielded disease control in 5.4 % of cases. CONCLUSIONS: The management of MPM in France is usually in accordance with guidelines. Response rates are somewhat lower than those described in clinical trials

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Hydrogen chloride emissions monitoring: European survey of practises, issues and opinions

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    This paper assesses the results from a survey on how hydrogen chloride (HCl) in stack gas emissions from industrial processes is measured by organisations based in Europe that do periodic short-term measurements. The survey was done by asking organisations to complete a questionnaire.The questions focused on the use of different monitoring techniques and the implementation of associated European monitoring methods (that is Committee of European Normalisation (CEN) standards).The results of the survey showed that there are a variety of different approaches used throughout Europe for the measurement of HCl. The preference remains for the use of a wet chemistry method, as opposed to automated systems. However, the survey has shown that the approach to determining the uncertainty of the wet chemistry method varies between test laboratories with some using an uncertainty provided by the analysis laboratory and others using a fixed uncertainty provided in the CEN standard.This work was part of a European Metrology Programme for Innovation and Research (EMPIR) project on “Determining new uncertainty requirements for increasingly stringent legislative HCl industrial emission limits” (18NRM04)

    Hydrogen chloride emissions monitoring: European survey of practises, issues and opinions

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    This paper assesses the results from a survey on how hydrogen chloride (HCl) in stack gas emissions from industrial processes is measured by organisations based in Europe that do periodic short-term measurements. The survey was done by asking organisations to complete a questionnaire.The questions focused on the use of different monitoring techniques and the implementation of associated European monitoring methods (that is Committee of European Normalisation (CEN) standards).The results of the survey showed that there are a variety of different approaches used throughout Europe for the measurement of HCl. The preference remains for the use of a wet chemistry method, as opposed to automated systems. However, the survey has shown that the approach to determining the uncertainty of the wet chemistry method varies between test laboratories with some using an uncertainty provided by the analysis laboratory and others using a fixed uncertainty provided in the CEN standard.This work was part of a European Metrology Programme for Innovation and Research (EMPIR) project on “Determining new uncertainty requirements for increasingly stringent legislative HCl industrial emission limits” (18NRM04)

    Contextualising adverse events of special interest to characterise the baseline incidence rates in 24 million patients with COVID-19 across 26 databases: a multinational retrospective cohort study

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    BACKGROUND: Adverse events of special interest (AESIs) were pre-specified to be monitored for the COVID-19 vaccines. Some AESIs are not only associated with the vaccines, but with COVID-19. Our aim was to characterise the incidence rates of AESIs following SARS-CoV-2 infection in patients and compare these to historical rates in the general population. METHODS: A multi-national cohort study with data from primary care, electronic health records, and insurance claims mapped to a common data model. This study's evidence was collected between Jan 1, 2017 and the conclusion of each database (which ranged from Jul 2020 to May 2022). The 16 pre-specified prevalent AESIs were: acute myocardial infarction, anaphylaxis, appendicitis, Bell's palsy, deep vein thrombosis, disseminated intravascular coagulation, encephalomyelitis, Guillain- Barré syndrome, haemorrhagic stroke, non-haemorrhagic stroke, immune thrombocytopenia, myocarditis/pericarditis, narcolepsy, pulmonary embolism, transverse myelitis, and thrombosis with thrombocytopenia. Age-sex standardised incidence rate ratios (SIR) were estimated to compare post-COVID-19 to pre-pandemic rates in each of the databases. FINDINGS: Substantial heterogeneity by age was seen for AESI rates, with some clearly increasing with age but others following the opposite trend. Similarly, differences were also observed across databases for same health outcome and age-sex strata. All studied AESIs appeared consistently more common in the post-COVID-19 compared to the historical cohorts, with related meta-analytic SIRs ranging from 1.32 (1.05 to 1.66) for narcolepsy to 11.70 (10.10 to 13.70) for pulmonary embolism. INTERPRETATION: Our findings suggest all AESIs are more common after COVID-19 than in the general population. Thromboembolic events were particularly common, and over 10-fold more so. More research is needed to contextualise post-COVID-19 complications in the longer term. FUNDING: None

    Model for screening of resonant magnetic perturbations by plasma in a realistic tokamak geometry and its impact on divertor strike points

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    This work addresses the question of the relation between strike-point splitting and magnetic stochasticity at the edge of a poloidally diverted tokamak in the presence of externally imposed magnetic perturbations. More specifically, ad-hoc helical current sheets are introduced in order to mimic a hypothetical screening of the external resonant magnetic perturbations by the plasma. These current sheets, which suppress magnetic islands, are found to reduce the amount of splitting expected at the target, which suggests that screening effects should be observable experimentally. Multiple screening current sheets reinforce each other, i.e. less current relative to the case of only one current sheet is required to screen the perturbation.Comment: Accepted in the Proceedings of the 19th International Conference on Plasma Surface Interactions, to be published in Journal of Nuclear Materials. Version 2: minor formatting and text improvements, more results mentioned in the conclusion and abstrac

    Use of anticoagulants and antiplatelet agents in stable outpatients with coronary artery disease and atrial fibrillation. International CLARIFY registry

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    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    Multipurpose use and water quality challenges in Lac de Guiers (Senegal)

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    Lac de Guiers (Guiers Lake) is a shallow lake in West Africa. Its waters are used mainly for irrigation and drinking water. Recent engineering in the Senegal River Valley has changed the lakes functioning and led to new water quality conditions. This article describes the water quality effects of the management of the lake and use of its waters, with special emphasis on salinity and eutrophication.</jats:p
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