90 research outputs found

    The effect of sample properties on the electron velocity in quantum Hall bars

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    We report on our theoretical investigation of the effects of the confining potential profile and sample size on the electron velocity distribution in (narrow) quantum-Hall systems. The electrostatic properties of the electron system are obtained by the Thomas-Fermi-Poisson nonlinear screening theory. The electron velocity distribution as a function of the lateral coordinate is obtained from the slope of the screened potential at the Fermi level and within the incompressible strips (ISs). We compare our findings with the recent experiments.Comment: 8 pages, 6 figure

    Investigation of the coupling asymmetries at double-slit interference experiments

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    Double-slit experiments inferring the phase and the amplitude of the transmission coefficient performed at quantum dots (QD), in the Coulomb blockade regime, present anomalies at the phase changes depending on the number of electrons confined. This phase change cannot be explained if one neglects the electron-electron interactions. Here, we present our numerical results, which simulate the real sample geometry by solving the Poisson equation in 3D. The screened potential profile is used to obtain energy eigenstates and eigenvalues of the QD. We find that, certain energy levels are coupled to the leads stronger compared to others. Our results give strong support to the phenomenological models in the literature describing the charging of a QD and the abrupt phase changes.Comment: conference paper, 50th anniversary of Aharonov-Bohm effec

    An application of EMS98 in a medium-sized city: The case of L’Aquila (Central Italy) after the April 6, 2009 Mw 6.3 earthquake

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    This paper describes the damage survey in the city of L’Aquila after the 6 April 2009 earthquake. The earthquake, whose magnitude and intensity reached Mw=6.3 and Imax=9–10 MCS, struck the Abruzzi region of Central Italy producing severe damage in L’Aquila and in many villages along theMiddle Aterno River valley. After the event, a building- to-building survey was performed in L’Aquila downtown aiming to collect data in order to perform a strict evaluation of the damage. The survey was carried out under the European Macroseismic Scale (EMS98) to evaluate the local macroseismic intensity. This damage survey represents the most complex application of the EMS98 in Italy since it became effective. More than 1,700 buildings (99% of the building stock) were taken into account during the survey at L’Aquila downtown, highlighting the difficult application of the macroseismic scale in a large urban context. The EMS98 revealed itself to be the best tool to perform such kind of analysis in urban settings. The complete survey displayed evidence of peculiar features in the damage distribution. Results revealed that the highest rate of collapses occurred within a delimited area of the historical centre and along the SW border of the fluvial terrace on which the city is settled. Intensity assessed for L’Aquila downtown was 8–9 EMS.Published67-801.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionaleJCR Journalrestricte

    Rilievo macrosismico del terremoto emiliano del 23 dicembre 2008

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    Questa nota presenta una sintesi delle attività svolte durante il rilievomacrosismico del terremoto avvenuto tra le province di Parma e Reggio Emilia il 23 dicembre 2008. La scossa di Ml 5.2 è stata localizzata a sud di Parma ed è stata avvertita in tutta l’Italia settentrionale e in gran parte della Liguria e della Toscana. Il presente rapporto illustra lemodalità di intervento del teamQUEST, relative al rilievo degli effetti e alla valutazione in intensità MCS in particolare per le località della zona epicentrale. L’ampia documentazione fotografica illustra alcuni dettagli delle tipologie di danneggiamento rilevate e consente di comprendere meglio le valutazioni dell’intensità macrosismica. This paper presents an overview of the activities performed during the macroseismic field survey of the earthquake that occurred in the Parma and Reggio Emilia region on December 23, 2008. The mainshock (Ml=5.2), was located south of the city of Parma and was resolutely felt through Northern Italy. The report here presented shows the procedures carried out by QUEST (Quick Earthquake Survey Team), concerning the survey. QUEST has been engaged in gathering the damage information and in assessing the macroseismic intensity, in particular about the epicentral area. A copious photo collection shows details of the observed damage nature and allows to better illustrate the intensit

    An application of EMS98 in a medium-sized city: the case of l’Aquila (Central Italy) after the april 6, 2009 mw 6.3 earthquake

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    This paper describes the damage survey in the city of L’Aquila after the 6 April 2009 earthquake. The earthquake, whose magnitude and intensity reached Mw=6.3 and Imax=10 MCS, struck the Abruzzi region of Central Italy producing severe damage in L’Aquila and in many villages along the Middle Aterno River valley. After the event, a building-to-building survey was performed in L’Aquila downtown aiming to collect data in order to perform a strict evaluation of the damage. The survey was carried out under the European Macroseismic Scale (EMS98) to evaluate the local macroseismic intensity. This damage survey represents the most complex application of the EMS98 in Italy since it became effective. More than 1700 buildings (99% of the building stock) were taken into account during the survey at L’Aquila downtown, highlighting the difficult application of the macroseismic scale in a large urban context. The EMS98 revealed itself to be the best tool to perform such kind of analysis in urban settings. The complete survey displayed evidence of peculiar features in the damage distribution. Results revealed that the highest rate of collapses occurred within a delimited area of the historical centre and along the SW border of the fluvial terrace on which the city is settled. Intensity assessed for L’Aquila downtown was 8-9 EMS

    An application of EMS98 in a medium-sized city: The case of L’Aquila (Central Italy) after the April 6, 2009 Mw 6.3 earthquake

    Get PDF
    This paper describes the damage survey in the city of L’Aquila after the 6 April 2009 earthquake. The earthquake, whose magnitude and intensity reached Mw=6.3 and Imax=9–10 MCS, struck the Abruzzi region of Central Italy producing severe damage in L’Aquila and in many villages along theMiddle Aterno River valley. After the event, a building- to-building survey was performed in L’Aquila downtown aiming to collect data in order to perform a strict evaluation of the damage. The survey was carried out under the European Macroseismic Scale (EMS98) to evaluate the local macroseismic intensity. This damage survey represents the most complex application of the EMS98 in Italy since it became effective. More than 1,700 buildings (99% of the building stock) were taken into account during the survey at L’Aquila downtown, highlighting the difficult application of the macroseismic scale in a large urban context. The EMS98 revealed itself to be the best tool to perform such kind of analysis in urban settings. The complete survey displayed evidence of peculiar features in the damage distribution. Results revealed that the highest rate of collapses occurred within a delimited area of the historical centre and along the SW border of the fluvial terrace on which the city is settled. Intensity assessed for L’Aquila downtown was 8–9 EMS

    L’indagine macrosismica: metodologia, parametri del terremoto, questioni aperte

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    Subito dopo l’evento del 6 aprile 2009, come di consueto è stata realizzata una lunga e complessa indagine macrosismica, promossa dal gruppo operativo QUEST, che ha avuto inizialmente l’obiettivo di delimitare l’area di danneggiamento, a supporto delle attività di pronto intervento della Protezione Civile, e successivamente quello di classificare nel modo più accurato e capillare possibile, gli effetti prodotti dall’evento, particolarmente nelle aree danneggiate. A questo scopo è stata prodotta una stima utilizzando la scala MCS (Sieberg, 1930); in un secondo momento è stata rifinita l’indagine per una cinquantina di località dell’area maggiormente danneggiata (Is MCS>VII), raccogliendo ed elaborando i dati in termini di scala macrosismica EMS98 (Grünthal, 1998). Per la complessità e la dimensione dei problemi affrontati, questo terremoto ha costituito un banco di prova di grande importanza per la macrosismologia italiana. In questo testo viene descritto il lavoro realizzato, discutendo in particolare alcuni aspetti che hanno messo alla prova le metodologie di indagine tradizionali (sistematiche irregolarità degli insediamenti monitorati, forti divergenze degli scenari di danno rispetto a quelli previsti dalle scale, difficile comparabilità con scenari storici, ecc.) e presentandone i risultati, in relazione ai parametri epicentrali che ne risultano e il loro contributo più diretto alla comprensione complessiva della sismicità dell’area

    The diagnostic suitability of a xerostomia questionnaire and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents

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    The study objective was to explore the diagnostic suitability of the Xerostomia Inventory and the association between xerostomia, hyposalivation and medication use in a group of nursing home residents. A cross-sectional study was carried out in 50 physically impaired nursing home residents (20 men) with a mean age of 78.1 years (range, 53–98) in The Netherlands. The Xerostomia Inventory-Dutch version was completed for all residents and the data were subjected to exploratory factor analysis to determine the diagnostic suitability. Residents’ data on xerostomia, whole saliva secretion rates and hyposalivation-related medications used were collected and statistically analyzed. The diagnostic suitability of the Xerostomia Inventory-Dutch version appeared restricted. The prevalence of xerostomia was 52%, without gender and age difference. The prevalence of hyposalivation was 24% for resting, 60% for chewing-stimulated and 18% for acid-stimulated whole saliva. All whole saliva secretion rates were significantly lower in women than in men and in older than in younger residents. Forty-four percent of all medications used were hyposalivation-related and women used significantly more medications than men. Xerostomia was significantly negatively correlated with the resting whole saliva secretion rate. The number of hyposalivation-related medications used was not significantly correlated with the various whole saliva secretion rates. In nursing home residents, xerostomia, hyposalivation and using hyposalivation-related medications seem common and partially associated features
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