177 research outputs found

    Constant angle surfaces in the Lorentzian Heisenberg group

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    In this paper, we define and, then, we characterize constant angle spacelike and timelike surfaces in the three-dimensional Heisenberg group, equipped with a 1-parameter family of Lorentzian metrics. In particular, we give an explicit local parametrization of these surfaces and we produce some examples.Comment: 13 pages, 8 figure

    Explicit Formulas for Non-Geodesic Biharmonic Curves of the Heisenberg Group

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    We consider the biharmonicity condition for maps between Riemannian manifolds (see [BK]), and study the non-geodesic biharmonic curves in the Heisenberg group H_3. First we prove that all of them are helices, and then we obtain explicitly their parametric equations.Comment: 16 pages, 2 figure

    a sonographic quantitative cutoff value of cerebral venous outflow in neurologic diseases a blinded study of 115 subjects

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    BACKGROUND AND PURPOSE: The autonomic nervous system maintains constant cerebral venous blood outflow in changing positions. Alterations in cerebral autoregulation can be revealed by postural changes at quantitative color Doppler sonography. The aim of this study was to reach an optimal cutoff value of the difference between the cerebral venous blood outflow in the supine and seated positions that can discriminate healthy controls from patients with multiple sclerosis and those with other neurologic diseases and to evaluate its specificity, sensitivity, and diagnostic accuracy. MATERIALS AND METHODS: One hundred fifteen subjects (54 with MS, 31 healthy controls, 30 with other neurologic diseases) underwent a blinded quantitative color Doppler sonography evaluation of cerebral venous blood outflow in the supine and sitting positions. An optimal difference value between the supine and sitting positions of the cerebral venous blood outflow cutoff value was sought. RESULTS: The difference value between supine and sitting positions of the cerebral venous blood outflow was ≤ 503.24 in 38/54 (70.37%) patients with MS, 9/31 (29.03%) healthy controls, and 13/30 (43.33%) subjects with other neurological diseases. A difference value between supine and sitting positions of the cerebral venous blood outflow at a 503.24 cutoff reached a sensitivity at 70.37%, a 70.96% specificity, a 80.85% positive predictive value, and a 57.89% negative predictive value; the quantitative color Doppler sonography parameters yielded significant differences. The difference value between supine and sitting positions of cerebral venous blood outflow ≤ 503.24 assessed the significant difference between MS versus other neurological diseases. CONCLUSIONS: Alteration of cerebral venous blood outflow discriminated MS versus other neurologic diseases and MS versus healthy controls. The difference value between supine and sitting positions of cerebral venous blood outflow ≤ 503.24 was statistically associated with MS

    Percutaneous injection of radiopaque gelified ethanol for the treatment of lumbar and cervical intervertebral disk herniations: experience and clinical outcome in 80 patients.

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    BACKGROUND AND PURPOSE: Chemonucleolysis represents a minimally invasive percutaneous technique characterized by an intradiskal injection of materials under fluoroscopic or CT guidance. Recently, a substance based on radiopaque gelified ethanol has been introduced. The purpose of this study was to describe the indications, procedure, safety, and efficacy of radiopaque gelified ethanol in the percutaneous treatment of cervical and lumbar disk herniations. MATERIALS AND METHODS: Between September 2010 and August 2013, 80 patients (32 women and 48 men; age range, 18–75 years) were treated for 107 lumbar disk herniations (L2–L3, n = 1; L3–L4, n = 15; L4–L5, n = 53; and L5–S1, n = 38) and 9 cervical disk herniations (C4–C5, n = 2; C5–C6, n = 2; C6–C7, n = 3; and C7–D1, n = 2) by percutaneous intradiskal injection of radiopaque gelified ethanol under fluoroscopic guidance. Thirty-six patients underwent a simultaneous treatment of 2 disk herniations. Patient symptoms were resistant to conservative therapy, with little or no pain relief after 4–6 weeks of physical therapy and drugs. All patients were evaluated by the Visual Analog Scale and the Oswestry Disability Index. RESULTS: Sixty-two of 73 (85%) patients with lumbar disk herniations and 6/7 (83%) patients with cervical disk herniations obtained significant symptom improvement, with a Visual Analog Scale reduction of at least 4 points and an Oswestry Disability Index reduction of at least 40%. Leakage of radiopaque gelified ethanol in the surrounding tissues occurred in 19 patients, however without any clinical side effects. CONCLUSIONS: In our experience, percutaneous intradiskal injection of radiopaque gelified ethanol is safe and effective in reducing the period of recovery from disabling symptoms

    Influenza D virus: Serological evidence in the Italian population from 2005 to 2017

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    Influenza D virus is a novel influenza virus, which was first isolated from an ailing swine in 2011 and later detected in cattle, suggesting that these animals may be a primary natural reservoir. To date, few studies have been performed on human samples and there is no conclusive evidence on the ability of the virus to infect humans. The aim of this serological study was to assess the prevalence of antibodies against influenza D virus in human serum samples collected in Italy from 2005 to 2017. Serum samples were analysed by haemagglutination inhibition and virus neutralization assays. The results showed that the prevalence of antibodies against the virus increased in the human population in Italy from 2005 to 2017, with a trend characterized by a sharp increase in some years, followed by a decline in subsequent years. The virus showed the ability to infect and elicit an immune response in humans. However, prevalence peaks in humans appear to follow epidemics in animals and not to persist in the human population

    The Wikiplantbase project: the role of amateur botanists in building up large online floristic databases

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    The Wikiplantbase project, started in 2013, provides a framework where the full set of georeferenced floristic records of Tuscany and Sardinia can be entered, stored, updated and freely accessed through the Internet. Mainly thanks to the collaboration of amateur botanists, data have accumulated quickly. All records entered by collaborators are submitted to the project coordinators, who are enabled to accept, modify, or reject them. As of 22 November 2016, Wikiplantbase #Toscana holds 116,402 verified floristic records (90% based on published literature, 5% on unpublished herbarium specimens, 5% on field observations), and Wikiplantbase #Sardegna 40,043 (77% published literature, 18% unpublished herbarium specimens, 5% on field observations ). The records include over 90% of the specific and subspecific taxa known for Tuscany and about 70% – but rapidly growing – of those known for Sardinia. The most recorded species are Quercus ilex L. (Fagaceae) for Tuscany and Pistacia lentiscus L. (Anacardiaceae) for Sardinia. With minor software tweaking, the online platform Wikiplantbase might be adopted in other contexts, resulting in a well connected network of regional floristic databases suited to exploit the involvement – still largely untapped – of nonacademic collaborators, as advocated by citizen science
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