1,294 research outputs found

    General integral relations for the description of scattering states using the hyperspherical adiabatic basis

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    In this work we investigate 1+2 reactions within the framework of the hyperspherical adiabatic expansion method. To this aim two integral relations, derived from the Kohn variational principle, are used. A detailed derivation of these relations is shown. The expressions derived are general, not restricted to relative ss partial waves, and with applicability in multichannel reactions. The convergence of the K{\cal K}-matrix in terms of the adiabatic potentials is investigated. Together with a simple model case used as a test for the method, we show results for the collision of a 4^4He atom on a \dimer dimer (only the elastic channel open), and for collisions involving a 6^6Li and two 4^4He atoms (two channels open).Comment: Accepted for publication in Physical Review

    Variational description of continuum states in terms of integral relations

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    Two integral relations derived from the Kohn Variational Principle (KVP) are used for describing scattering states. In usual applications the KVP requires the explicit form of the asymptotic behavior of the scattering wave function. This is not the case when the integral relations are applied since, due to their short range nature, the only condition for the scattering wave function Ψ\Psi is that it be the solution of (H−E)Ψ=0(H-E)\Psi=0 in the internal region. Several examples are analyzed for the computation of phase-shifts from bound state type wave functions or, in the case of the scattering of charged particles, it is possible to obtain phase-shifts using free asymptotic conditions. As a final example we discuss the use of the integral relations in the case of the Hyperspherical Adiabatic method.Comment: 34 pages, 7 figures, accepted in Phys. Rev.

    The helium trimer with soft-core potentials

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    The helium trimer is studied using two- and three-body soft-core potentials. Realistic helium-helium potentials present an extremely strong short-range repulsion and support a single, very shallow, bound state. The description of systems with more than two helium atoms is difficult due to the very large cancellation between kinetic and potential energy. We analyze the possibility of describing the three helium system in the ultracold regime using a gaussian representation of a widely used realistic potential, the LM2M2 interaction. However, in order to describe correctly the trimer ground state a three-body force has to be added to the gaussian interaction. With this potential model the two bound states of the trimer and the low energy scattering helium-dimer phase shifts obtained with the LM2M2 potential are well reproduced.Comment: 15 pages, 3 figures, submitted to Few-Body System

    Stato dell’arte dei Piani di Emergenza per il Massiccio Afflusso di Feriti (PEMAF) negli ospedali italiani. Studio pilota

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    Aim of this study is to assess the level of implementation of plans for the massive influx of injured (PEMAF) in Italian hospitals. An anonymous questionnaire was administered to a sample of 100 hospitals selected through the network of the Italian Society of Emergency Medicine (SIMEU). Each answer of the questionnaire was assigned a score, then reported on a scale of compliance (maximum 65 points, threshold 35 points). The average scores were analyzed by hospital’s venue, level of activity and previous experience of managing a real emergency. Student’s t-test was used to compare means. Thirty-two hospitals sent the questionnaire, representing 33% of those selected. Five were excluded for incomplete data. The data analyzed refers to 27 hospitals of various levels of complexity, from all around the country: 55.6% from the Northern Section, 22.2% from the Centre and 22.2% from the Southern section and the Islands; and only 55.6% are above the minimum threshold of compliance. The weakest PEMAF’s area is the one related to the specific training of health workers, therefore the percentage of hospitals complying the requirements in this field is down to 37%. Ten hospitals (37%) had managed a real maxi-emergence in the past: belonging to such group of hospitals is associated with an average level of compliance significantly higher than the others (p<0,005). Due to a limited percentage of responders, the study involved so far a too small amount of hospitals; happily, they were evenly distributed in the different sections of the Country; therefore it will be appropriate to obtain a larger compliance before reaching clear-cut conclusions, but it already appears that the most critical point is the lack of specific education to maxi-emergencies in the hospital personnel

    Seasonal variations in eelgrass (Zostera marina l.) responses to nutrients availability.

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    Relationship between water column and pore water nutrient concentrations on the growth of the Zostera marina L. in the Numana harbour (Adriatic Sea) was investigated. High concentrations of dissolved inorganic nitrogen in the water column and in the pore water were not related with plant growth. In contrast phosphate concentrations in the water column appeared a limiting factor

    Posidonia oceanica (L.) delile dampens cell migration of human neuroblastoma cells

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    Neuroblastoma (NB) is a common cancer in childhood, and lethal in its high-risk form, primarily because of its high metastatic potential. Targeting cancer cell migration, and thus preventing metastasis formation, is the rationale for more effective cancer therapy against NB. Previous studies have described the leaf extract from Posidonia oceanica marine plant (POE) as an antioxidant, anti-inflammatory agent and inhibitor of cancer cell migration. This study aims to examine the POE anti-migratory role in human SH-SY5Y neuroblastoma cells and the underlying mechanisms of action. Wound healing and gelatin zymography assays showed that POE at early times inhibits cell migration and reduces pro-MMP-2 release into culture medium. By monitoring expression level of key autophagy markers by Western blot assay, a correlation between POE-induced cell migration inhibition and autophagy activation was demonstrated. Cell morphology and immunofluorescence analyses showed that POE induces neurite formation and neuronal differentiation at later times. These results suggest POE might act against cell migration by triggering early nontoxic autophagy. The POE-induced cellular morphological change toward cell differentiation might contribute to prolonging the phytocomplex anti-migratory effect to later times. Overall, these results encourage future in vivo studies to test POE applicability in neuroblastoma treatment

    Integral relations for three-body continuum states with the adiabatic expansion

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    Application of the Hyperspherical Adiabatic expansion to describe three-body scattering states suffers the problem of a very slow convergence. Contrary to what happens for bound states, a huge number of hyperradial equations has to be solved, and even if done, the extraction of the scattering amplitude is problematic. In this paper we show how to obtain accurate scattering phase shifts using the Hyperspherical Adiabatic expansion. To this aim two integral relations, derived from the Kohn Variational Principle, are used. The convergence of this procedure is as fast as for bound states.Comment: 4 pages, 1 figur

    Oral contraceptives combined with interferon β in multiple sclerosis

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    Objective: To test the effect of oral contraceptives (OCs) in combination with interferon b (IFN-b) on disease activity in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: One hundred fifty women with RRMS were randomized in a 1:1:1 ratio to receive IFNb-1a subcutaneously (SC) only (group 1), IFN-b-1a SC plus ethinylstradiol 20 mg and desogestrel 150 mg (group 2), or IFN-b-1a SC plus ethinylestradiol 40 mg and desogestrel 125 mg (group 3). The primary endpoint was the cumulative number of combined unique active (CUA) lesions on brain MRI at week 96. Secondary endpoints included MRI and clinical and safety measures. Results: The estimated number of cumulative CUA lesions at week 96 was 0.98 (95% confidence interval [CI] 0.81–1.14) in group 1, 0.84 (95% CI 0.66–1.02) in group 2, and 0.72 (95% CI 0.53–0.91) in group 3, with a decrease of 14.1% (p 5 0.24) and 26.5% (p 5 0.04) when comparing group 1 with groups 2 and 3, respectively. The number of patients with no gadoliniumenhancing lesions was greater in group 3 than in group 1 (p 5 0.03). No significant differences were detected in other secondary endpoints. IFN-b or OC discontinuations were equally distributed across groups. Conclusions: Our results translate the observations derived from experimental models to patients, supporting the anti-inflammatory effects of OCs with high-dose estrogens, and suggest possible directions for future research
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