2,464 research outputs found

    Bose-Einstein Correlations in Multihadron Events at LEP

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    Bose-Einstein correlations in pairs of identical particles were analyzed in e+ e- multihadron annihilations at ~91.2 GeV at LEP. The first studies involved identical charged pions and the emitting source size was determined. Then the study of charged kaons suggested that the radius depends on the mass of the emitted particles. Subsequenty the dependence of the source radius on the event multiplicity was analyzed. The study of the correlations in neutral pions and neutral kaons extended these concepts to neutral particles. The shape of the source was analyzed in 3 dimensions and was found not to be spherically symmetric. In recent studies at LEP the correlations were analyzed in intervals of the average pair transverse momentum and of the pair rapidity to study the correlations between the pion production points and their momenta (position-momentum correlations). The latest e+ e- data are consistent with an expanding source.Comment: 8 pages, 10 eps figures. Invited paper at the ``Ninth Workshop on Non Perturbative QCD'', Institut d'Astrophysique de Paris, Paris, France, 4-8 June 200

    IORT with mobile linacs: the Italian experience

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    The significance of GATA3 expression in breast cancer: a 10-year follow-up study.

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    GATA3 is a transcription factor closely associated with estrogen receptor alpha in breast carcinoma, with a potential prognostic utility. This study investigated the immunohistochemical expression of GATA3 in estrogen receptor alpha-positive and estrogen receptor alpha-negative breast carcinomas. One hundred sixty-six cases of invasive breast carcinomas with 10-year follow-up information were analyzed. Positive GATA3 and estrogen receptor alpha cases were defined as greater than 20% of cells staining. Time to cancer recurrence and time to death were analyzed with survival methods. Of 166 patients, 40 were estrogen receptor alpha negative and 121 estrogen receptor alpha positive. Thirty-eight (23%) recurrences and 51 (31%) deaths were observed. In final multivariable analyses, GATA3-positive tumors had about two thirds the recurrence risk of GATA3-negative tumors (hazard ratio = 0.65, P = .395) and comparable mortality risk (hazard ratio = 0.86, P = .730). In prespecified subgroup analyses, the protective effect of GATA3 expression was most pronounced among estrogen receptor alpha-positive patients who received tamoxifen (hazard ratio = 0.57 for recurrence and 0.68 for death). We found no statistically significant differences in recurrence or survival rates between GATA3-positive and GATA3-negative tumors. However, there was a suggestion of a modest-to-strong protective effect of GATA3 expression among estrogen receptor alpha-positive patients receiving hormone therapy

    A fast - Monte Carlo toolkit on GPU for treatment plan dose recalculation in proton therapy

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    In the context of the particle therapy a crucial role is played by Treatment Planning Systems (TPSs), tools aimed to compute and optimize the tratment plan. Nowadays one of the major issues related to the TPS in particle therapy is the large CPU time needed. We developed a software toolkit (FRED) for reducing dose recalculation time by exploiting Graphics Processing Units (GPU) hardware. Thanks to their high parallelization capability, GPUs significantly reduce the computation time, up to factor 100 respect to a standard CPU running software. The transport of proton beams in the patient is accurately described through Monte Carlo methods. Physical processes reproduced are: Multiple Coulomb Scattering, energy straggling and nuclear interactions of protons with the main nuclei composing the biological tissues. FRED toolkit does not rely on the water equivalent translation of tissues, but exploits the Computed Tomography anatomical information by reconstructing and simulating the atomic composition of each crossed tissue. FRED can be used as an efficient tool for dose recalculation, on the day of the treatment. In fact it can provide in about one minute on standard hardware the dose map obtained combining the treatment plan, earlier computed by the TPS, and the current patient anatomic arrangement

    Tremor in motor neuron disease may be central rather than peripheral in origin

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    BACKGROUND AND PURPOSE: Motor neuron disease (MND) refers to a spectrum of degenerative diseases affecting motor neurons. Recent clinical and post-mortem observations have revealed considerable variability in the phenotype. Rhythmic involuntary oscillations of the hands during action, resembling tremor, can occur in MND, but their pathophysiology has not yet been investigated. METHODS: A total of 120 consecutive patients with MND were screened for tremor. Twelve patients with action tremor and no other movement disorders were found. Ten took part in the study. Tremor was recorded bilaterally using surface electromyography (EMG) and triaxial accelerometer, with and without a variable weight load. Power spectra of rectified EMG and accelerometric signal were calculated. To investigate a possible cerebellar involvement, eyeblink classic conditioning was performed in five patients. RESULTS: Action tremor was present in about 10% of our population. All patients showed distal postural tremor of low amplitude and constant frequency, bilateral with a small degree of asymmetry. Two also showed simple kinetic tremor. A peak at the EMG and accelerometric recordings ranging from 4 to 12 Hz was found in all patients. Loading did not change peak frequency in either the electromyographic or accelerometric power spectra. Compared with healthy volunteers, patients had a smaller number of conditioned responses during eyeblink classic conditioning. CONCLUSIONS: Our data suggest that patients with MND can present with action tremor of a central origin, possibly due to a cerebellar dysfunction. This evidence supports the novel idea of MND as a multisystem neurodegenerative disease and that action tremor can be part of this condition

    Ontology-Driven Food Category Classification in Images

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    The self-management of chronic diseases related to dietary habits includes the necessity of tracking what people eat. Most of the approaches proposed in the literature classify food pictures by labels describing the whole recipe. The main drawback of this kind of strategy is that a wrong prediction of the recipe leads to a wrong prediction of any ingredient of such a recipe. In this paper we present a multi-label food classification approach, exploiting deep neural networks, where each food picture is classified with labels describing the food categories of the ingredients in each recipe. The aim of our approach is to support the detection of food categories in order to detect which one might be dangerous for a user affected by chronic disease. Our approach relies on background knowledge where recipes, food categories, and their relatedness with chronic diseases are modeled within a state-of-the-art ontology. Experiments conducted on a new publicly released dataset demonstrated the effectiveness of the proposed approach with respect to state-of-the-art classification strategies

    tDCS changes in motor excitability are specific to orientation of current flow

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    BACKGROUND: Measurements and models of current flow in the brain during transcranial Direct Current Stimulation (tDCS) indicate stimulation of regions in-between electrodes. Moreover, the folded cortex results in local fluctuations in current flow intensity and direction, and animal studies suggest current flow direction relative to cortical columns determines response to tDCS. METHODS: Here we test this idea by using Transcranial Magnetic Stimulation Motor Evoked Potentials (TMS-MEP) to measure changes in corticospinal excitability following tDCS applied with electrodes aligned orthogonal (across) or parallel to M1 in the central sulcus. RESULTS: Current flow models predicted that the orthogonal electrode montage produces consistently oriented current across the hand region of M1 that flows along cortical columns, while the parallel electrode montage produces non-uniform current directions across the M1 cortical surface. We find that orthogonal, but not parallel, orientated tDCS modulates TMS-MEPs. We also show modulation is sensitive to the orientation of the TMS coil (PA or AP), which is thought to select different afferent pathways to M1. CONCLUSIONS: Our results are consistent with tDCS producing directionally specific neuromodulation in brain regions in-between electrodes, but shows nuanced changes in excitability that are presumably current direction relative to column and axon pathway specific. We suggest that the direction of current flow through cortical target regions should be considered for targeting and dose-control of tDCS

    Multiple isolated aneurysms in a case of “burned out” Takayasu aortitis

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    AbstractTakayasu aortitis (TA) is a chronic inflammatory disease predominantly seen in young Asian women. The disease is idiopathic and largely affects the aorta and its major branches. The basic pathologic changes in TA are fibrosis and subsequent occlusion of the large arteries. TA is classically termed “pulseless” disease, with manifestations during the occlusive stage including limb ischemia, renovascular hypertension, and heart failure. Arterial dilation and aneurysm are largely unappreciated manifestations of TA, but they occur in as many as 32% of affected patients. We report chronic “burned out” TA in a 23-year-old Hispanic woman with isolated aneurysms of the descending thoracic aorta, abdominal aorta, and common iliac arteries, without occlusive disease. (J Vasc Surg 2003;37:1094-7.
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