1,282 research outputs found

    Cyclic Fluctuations, Climatic Changes and Role of Noise in Planktonic Foraminifera in the Mediterranean Sea

    Get PDF
    The study of Planktonic Foraminifera abundances permits to obtain climatic curves on the basis of percentage ratio between tropical and temperate/polar forms. Climatic changes were controlled by several phenomena as: (i) Milankovitch's cycles, produced by variations of astronomical parameters such as precession, obliquity and eccentricity; (ii) continental geodynamic evolution and orogenic belt; (iii) variations of atmospheric and oceanic currents; (iv) volcanic eruptions; (v) meteor impacts. But while astronomical parameters have a quasi-regular periodicity, the other phenomena can be considered as "noise signal" in natural systems. The interplay between cyclical astronomical variations, the "noise signal" and the intrinsic nonlinearity of the ecologic system produces strong glacial or interglacial period according to the stochastic resonance phenomenon.Comment: 6 pages, 4 figure

    The immunohistochemical expression of leptin in lymph node metastasis from laryngeal squamous cell carcinoma (SCC)

    Get PDF
    Introduction: Leptin is a proteohormone produced predominantly by white adipocytes and primarily known for its key role in the control of food intake and sense of satiety. From its discover leptin has been found in different body districts, involved in always new functions and processes. In the last years numerous relationships between leptin and cancer has been found. The aim of this study is to test the leptin positivity in human primitive laryngeal squamous cell carcinoma (SCC) and in its lymph node metastasis. Materials and methods: Leptin positivity was detected by immunohistochemical analysis on pathological samples from 18 patients subjected to laryngectomy and neck dissection for SCC. Results: During the study we pointed out a statistically significant relationship (p < 0.05) between leptin positivity levels and tumor differentiation grade, in particular we observed that a decrease in tumor leptin production correlates with higher level of cancer histological dedifferentiation. Conclusion: Our research on leptin expression in laryngeal squamous neoplastic pathology is aimed to the attempt of establishing a more precise patient risk stratification thanks to a new marker able to give a contribution to the identification of patient with poor prognosis and at risk of failure of actual standard therapy

    Study of the ground-state energy of 40Ca with the CD-Bonn nucleon-nucleon potential

    Full text link
    We have calculated the ground-state energy of the doubly-magic nucleus 40Ca within the framework of the Goldstone expansion using the CD-Bonn nucleon-nucleon potential. The short-range repulsion of this potential has been renormalized by integrating out its high-momentum components so as to derive a low-momentum potential V-low-k defined up to a cutoff momentum Lambda. A simple criterion has been employed to establish a connection between this cutoff momentum and the size of the two-nucleon model space in the harmonic oscillator basis. This model-space truncation approach provides a reliable way to renormalize the free nucleon-nucleon potential preserving its many-body physics. The role of the 3p-3h and 4p-4h excitations in the description of the ground state of 40Ca is discussed.Comment: 4 pages, 1 figure, 1 table, to be published in Physical Review

    Shell-model study of the N=82 isotonic chain with a realistic effective hamiltonian

    Full text link
    We have performed shell-model calculations for the even- and odd-mass N=82 isotones, focusing attention on low-energy states. The single-particle energies and effective two-body interaction have been both determined within the framework of the time-dependent degenerate linked-diagram perturbation theory, starting from a low-momentum interaction derived from the CD-Bonn nucleon-nucleon potential. In this way, no phenomenological input enters our effective Hamiltonian, whose reliability is evidenced by the good agreement between theory and experiment.Comment: 7 pages, 11 figures, 3 tables, to be published in Physical Review

    Ceftolozane/tazobactam for resistant drugs pseudomonas aeruginosa respiratory infections: A systematic literature review of the real-world evidence

    Get PDF
    Background: Ceftolozane/tazobactam (C/T) is a β-lactam/β-lactamase inhibitor combination that mainly targets Gram-negative bacteria. The current international guidelines recommend including C/T treatment in the empirical therapy for hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Pseudomonas aeruginosa (PA) is one of the most challenging Gram-negative bacteria. We conducted a systematic review of all cases reported in the literature to summarize the existing evidence. Methods: The main electronic databases were screened to identify case reports of patients with drug-resistant PA respiratory infections treated with C/T. Results: A total of 22 publications were included for a total of 84 infective episodes. The clinical success rate was 72.6% across a wide range of comorbidities. The 45.8% of patients treated with C/T presented colonization by PA. C/T was well tolerated. Only six patients presented adverse events, but none had to stop treatment. The most common therapeutic regimens were 1.5 g every 8 h and 3 g every 8 h. Conclusion: C/T may be a valid therapeutic option to treat multidrug-resistant (MDR), extensively drug-resistant (XDR), pandrug-resistant (PDR), and carbapenem-resistant (CR) PA infections. However, further data are necessary to define the optimal treatment dosage and duration

    Nodular AL Amyloidosis — An Unusual Etiology of a Solitary Pulmonary Nodule

    Get PDF
    Solitary pulmonary nodules (SPN) are defined as single intraparenchymal opacities less than 3 centimeters. The differential diagnosis of the SPN is broad. AL amyloidosis is a protein conformational disease which occurs when certain monoclonal light chains develop an unstable tertiary structure with resultant polymerization of insoluble amyloid fibrils that deposit in the extracellular space of sundry tissues. In the lung, diffuse interstitial amyloid deposition is the most common form of the disease

    STUDY OF THE O-18+Ni-64 TWO-NEUTRON TRANSFER REACTION AT 84 MeV BY MAGNEX

    Get PDF
    A study of the two-neutron transfer reaction of the O-18 + Ni-64 system at 84 MeV incident energy to the ground and first 2(+) excited state of the residual Ni-66 nucleus is presented. The experiment was performed at the INFN-LNS (Italy) by using the large acceptance MAGNEX spectrometer. Theoretical models are used in order to disentangle the competition between long-range and short-range correlations

    Long-range versus short-range correlations in the two-neutron transfer reaction Ni 64 (O 18, O 16) Ni 66

    Get PDF
    Recently, various two-neutron transfer studies using the (18O,16O) reaction were performed with a large success. This was achieved because of a combined use of the microscopic quantum description of the reaction mechanism and of the nuclear structure. In the present work we use this methodology to study the two-neutron transfer reaction of the 18O+64Ni system at 84 MeV incident energy, to the ground and first 2+ excited state of the residual 66Ni nucleus. All the experimental data were measured by the large acceptance MAGNEX spectrometer at the Instituto Nazionale di Fisica Nucleare \u2013Laboratori Nazionali del Sud (Italy). We have performed exact finite range cross section calculations using the coupled channel Born approximation (CCBA) and coupled reaction channel (CRC) method for the sequential and direct two-neutron transfers, respectively. Moreover, this is the first time that the formalism of the microscopic interaction boson model (IBM-2) was applied to a two-neutron transfer reaction. From our results we conclude that for two-neutron transfer to the ground state of 66Ni, the direct transfer is the dominant reaction mechanism, whereas for the transfer to the first excited state of 66Ni, the sequential process dominates. A competition between long-range and short-range correlations is discussed, in particular, how the use of two different models (Shell model and IBM's) help to disentangle long- and short-range correlations
    • …
    corecore