688 research outputs found

    Slow Light amplification in a non-inverted gain medium

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    We investigate the propagation of a coherent probe light pulse through a three-level atomic medium (in the Λ\Lambda--configuration) in the presence of a pump laser under the conditions for gain without inversion. When the carrier frequency of the probe pulse and the pump laser are in a Raman configuration, we show that it is possible to amplify a slow propagating pulse. We also analyze the regime in which the probe pulse is slightly detuned from resonance where we observe anomalous light propagation.Comment: 7 pages, 10 figures. To be published in Europhysics Letter

    Primary headaches in children: clinical findings on the association with other conditions.

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    The aim of the present study is to report on the frequency of some comorbidities in primary headaches in childhood. Two hundred and eighty children (175 males and 105 females; ratio 1.7:1), aged 4 to 14 years, affected by primary headaches were consecutively enrolled in this study. In direct interviews, parents and children gave information about the association of their headaches with different conditions including asthma and allergic disorders, convulsive episodes, sleep disorders and increased body weight, affections some time associated in the literature to headache as comorbidities. In addition, anxiety and depression, attention deficit/hyperactivity disorder, tics, learning disabilities and obsessive-compulsive disorders, using psycho-diagnostic scales were evaluated. Two hundred and eighty children matched for age, sex, race and socio-economic status, were used as controls. No significant association of primary headaches was found with asthma and allergic disorders, convulsive episodes, sleep disorders and increased body weight. Overall behavioral disorders were more common in children who experienced headache than in controls. A significant association of primary headache was found with anxiety and depression (p value <0.001), but not with the other psychiatric disorders. Primary headaches in children are not associated with most of the psychiatric and systemic conditions herein investigated. On the contrary, there was a significant association with anxiety and depression, as frequently reported in adults

    The phonon dispersion of graphite by inelastic x-ray scattering

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    We present the full in-plane phonon dispersion of graphite obtained from inelastic x-ray scattering, including the optical and acoustic branches, as well as the mid-frequency range between the KK and MM points in the Brillouin zone, where experimental data have been unavailable so far. The existence of a Kohn anomaly at the KK point is further supported. We fit a fifth-nearest neighbour force-constants model to the experimental data, making improved force-constants calculations of the phonon dispersion in both graphite and carbon nanotubes available.Comment: 7 pages; submitted to Phys. Rev.

    Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation

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    In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X.EURATOM 63305

    Cortical metabolic arrangement during olfactory processing:proposal for a 18F-FDG PET/CT methodological approach

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    The aim of this article is to investigate the cortical metabolic arrangements in olfactory processing by using 18F fluorodeoxyglucose (FDG) positron emission tomography/computed tomography. Twenty-six normosmic individuals (14 women and 12 men; mean age 46.710 years) were exposed to a neutral olfactory condition (NC) and, after 1 month, to a pure olfactory condition (OC) in a relatively ecological environment, that is, outside the scanner. All the subjects were injected with 185-210 megabecquerel of 18F FDG during both stimulations. Statistical parametric mapping version 2 was used in order to assess differences between NC and OC. As a result, we found a significant higher glucose consumption during OC in the cuneus, lingual, and parahippocampal gyri, mainly in the left hemisphere. During NC, our results show a relative higher glucose metabolism in the left superior, inferior, middle, medial frontal, and orbital gyri as well as in the anterior cingulate cortex. The present investigation, performed with a widely available functional imaging clinical tool, may help to better understand the neural responses associated to olfactory processing in healthy individuals and in patients with olfactory disorders by acquiring data in an ecologic, noise-free, and resting condition in which possible cerebral activations related to unwanted attentional processes might be avoided

    Resezioni polmonari limitate “intenzionali” versus lobectomie nel trattamento dei tumori polmonari periferici non microcitomi allo stadio IA

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    Scopo del presente studio è valutare, attraverso l’analisi retrospettiva della nostra casistica e la revisione della letteratura, se le resezioni polmonari limitate siano equivalenti alla lobectomia nel trattamento dei tumori polmonari non microcitomi (NSCLC) periferici allo stadio IA (T1N0M0), in termini di radicalità oncologica, sopravvivenza e tasso di recidive locali, regionali e sistemiche.Viene inoltre preso in considerazione l’impatto delle resezioni limitate, rispetto alle resezioni lobari, sulla funzionalità polmonare postoperatoria. Pazienti e metodi. Abbiamo analizzato una serie consecutiva di 36 pazienti, 28 uomini e 8 donne, di età compresa fra 61 e 81 anni (media 73 anni), sottoposti ad intervento chirurgico, nel periodo compreso fra gennaio 2000 e dicembre 2003, per NSCLC periferici T1N0M0; sono state effettuate 11 resezioni limitate e 25 lobectomie. Sono state analizzate comparativamente sopravvivenza e recidive (follow-up 3-5 anni), nonché le prove di funzionalità respiratoria ad un anno dall’intervento. Risultati. La sopravvivenza a 3 e 5 anni è stata pari all’88% ed all’82% nel gruppo dei pazienti sottoposti a resezioni limitate, al 93% e all’88% nel gruppo dei pazienti sottoposti a lobectomia. Si è verificata una recidiva locale (9%) nel primo gruppo, una (4%) nel secondo. Ad un anno dall’intervento si sono osservati un moderato decremento del volume espiratorio forzato in 1 secondo (FEV1) e della capacità di diffusione per monossido di carbonio (DLCO) nei pazienti sottoposti a resezione lobare, e un sostanziale mantenimento dei parametri funzionali preoperatori, eccezion fatta per la DLCO, nei pazienti sottoposti a resezione limitata. Conclusioni. La nostra circoscritta esperienza, in accordo con le tendenze attuali della letteratura, indica che l’intervento di resezione polmonare limitata, in pazienti selezionati, con NSCLC periferici allo stadio IA, rappresenta una valida alternativa alla lobectomia in termini di sopravvivenza e tasso di recidiva, determinando altresì un minor decremento della funzionalità polmonare postoperatoria. La segmentectomia può essere dunque considerata, in tali casi, procedura chirurgica di scelta, anche in pazienti in grado di tollerare una resezione maggior

    A Guide to Perform 3D Histology of Biological Tissues with Fluorescence Microscopy

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    The analysis of histological alterations in all types of tissue is of primary importance in pathology for highly accurate and robust diagnosis. Recent advances in tissue clearing and fluorescence microscopy made the study of the anatomy of biological tissue possible in three dimensions. The combination of these techniques with classical hematoxylin and eosin (H&amp;E) staining has led to the birth of three-dimensional (3D) histology. Here, we present an overview of the state-of-the-art methods, highlighting the optimal combinations of different clearing methods and advanced fluorescence microscopy techniques for the investigation of all types of biological tissues. We employed fluorescence nuclear and eosin Y staining that enabled us to obtain hematoxylin and eosin pseudo-coloring comparable with the gold standard H&amp;E analysis. The computational reconstructions obtained with 3D optical imaging can be analyzed by a pathologist without any specific training in volumetric microscopy, paving the way for new biomedical applications in clinical pathology
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