598 research outputs found

    Quantum Return Probability for Substitution Potentials

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    We propose an effective exponent ruling the algebraic decay of the average quantum return probability for discrete Schrodinger operators. We compute it for some non-periodic substitution potentials with different degrees of randomness, and do not find a complete qualitative agreement with the spectral type of the substitution sequences themselves, i.e., more random the sequence smaller such exponent.Comment: Latex, 13 pages, 6 figures; to be published in Journal of Physics

    What determines the spreading of a wave packet?

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    The multifractal dimensions D2^mu and D2^psi of the energy spectrum and eigenfunctions, resp., are shown to determine the asymptotic scaling of the width of a spreading wave packet. For systems where the shape of the wave packet is preserved the k-th moment increases as t^(k*beta) with beta=D2^mu/D2^psi, while in general t^(k*beta) is an optimal lower bound. Furthermore, we show that in d dimensions asymptotically in time the center of any wave packet decreases spatially as a power law with exponent D_2^psi - d and present numerical support for these results.Comment: Physical Review Letters to appear, 4 pages postscript with figure

    The presence of dominant follicles and corpora lutea does not perturb response to controlled ovarian stimulation in random start protocols

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    The advent of random start protocols to shorten the time needed to store oocytes in women with malignancies has represented an important improvement in the field of fertility preservation. However, Randomized Controlled Trials are difficult to implement in this area and available evidence that supports this approach remains modest. To shed more light on this issue, we compared the follicular development between the ovary carrying the dominant follicle or the corpus luteum and the contralateral resting ovary in 90 women who underwent random start controlled ovarian stimulation (COS). In fact, ovarian response did not differ between the two ovaries. Subgroup analyses according to the phase of the cycle at the initiation of COS, the type of malignancy, the use of letrozole and the magnitude of the ovarian response did not allow to identify any condition showing a difference in the follicular response between the active and the resting ovaries. In conclusion, follicular growth does not seem to be perturbed by the presence of a dominant follicle or a corpus luteum

    Autologous micrografts and methotrexate in plantar erosive lichen planus: healing and pain control. A case report

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    Erosive lichen planus is an uncommon variant of lichen planus. We report a case of long-standing and refractory plantar ELPs causing disabling and opiate-resistant pain treated with 'classic' meshed skin graft combined with RigeneraVR micrografts. After approximately 9 months follow-up, no clinical recurrence or pain were observed. Erosive lichen planus (ELP) is an uncommon variant of lichen planus, involving oral cavity and genitalia and, less often plantar areas, where it usually presents with chronic erosions of the soles, along with intense, disabling pain and progressive loss of toenails. An abnormal immune cellular response (CD8+ lymphocytes and macrophages) and the consequent altered production of multiple mediators (interleukin-12, interferon-gamma, tumor necrosis factor-alpha, RANTES and MMP-9), seem to play a crucial role in the pathogenesis, although the etiology remains uncertain. From a histological point of view, ELP shows keratinocyte apoptosis, intense inflammatory response and basal epithelial keratinocytes TNF-alpha overexpression. Several therapies have been proposed, with variable and controversial results. While topical corticosteroids and topical calcineurin inhibitors are the treatments of choice for localized forms, short pulses of systemic glucocorticoids, phototherapy, and systemic immunosuppressants are recommended for generalized cases. Surgery has been reported as a possible therapeutic option in refractory and stable cases with localized lesions, either alone or with cyclosporine. Herein, we report a case of longstanding and refractory plantar ELPS causing disabling and opiate-resistant pain treated with 'classic' meshed skin graft combined with RigeneraVR micrografts

    Double butterfly spectrum for two interacting particles in the Harper model

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    We study the effect of interparticle interaction UU on the spectrum of the Harper model and show that it leads to a pure-point component arising from the multifractal spectrum of non interacting problem. Our numerical studies allow to understand the global structure of the spectrum. Analytical approach developed permits to understand the origin of localized states in the limit of strong interaction UU and fine spectral structure for small UU.Comment: revtex, 4 pages, 5 figure

    Near-infrared spectroscopy of extreme BAL QSOs from the QUBRICS bright quasar survey

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    We report on the spectral confirmation of 18 quasi-stellar object (QSO) candidates from the QUasars as BRIght beacons for Cosmology in the Southern hemisphere (QUBRICS) survey, previously observed in the optical band, for which we acquired new spectroscopic data in the near-infrared band with the Folded-port InfraRed Echellette (FIRE) spectrograph at the Magellan Baade telescope. In most cases, further observations were prompted by the peculiar nature of the targets, whose optical spectra displayed unexpected absorption features. All candidates have been confirmed as bona fide QSOs, with average emission redshift z ≃ 2.1. The analysis of the emission and absorption features in the spectra, performed with astrocook and QSFit, reveals that the large majority of these objects are broad absorption line (BAL) QSOs, with almost half of them displaying strong Fe ii absorption (typical of the so-called FeLoBAL QSOs). The detection of such a large fraction of rare objects (which are estimated to account for less than 1 per cent of the general QSO population) is interpreted as an unexpected (yet favourable) consequence of the particular candidate selection procedure adopted within the QUBRICS survey. The measured properties of FeLoBAL QSOs observed so far provide no evidence that they are a manifestation of a particular stage in active galactic nucleus (AGN) evolution. In this paper, we present an explorative analysis of the individual QSOs, to serve as a basis for a further, more detailed investigation

    INFLAMMATORY BOWEL DISEASE (IBD) IN PREGNANCY: ANALYSIS OF THE POSSIBLE EFFECTS OF THE DISEASE ON THE FETUS AND THE NEWBORN AND THERAPEUTIC APPROACHES

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    The Inflammatory Bowel Diseases(IBD), are a group of inflammatory diseases characterized by the presence of chronic inflammation, i the absenc of infectious ethiology. The two most well-known diseases in this group are: Crohn's disease (CD) and Ulcerative Colitis (UC). In cases where iti is not possible to distinguish between CD and UC, it is called Indeterminated Colitis. IBD can affect women pregnant. The causes of IBD are unknown, and the clinical course of the sdisease is characterized by phases of activity and remission. UC is a chronic inflammation of the mucosa of the colon and involving predominantly the left colon and rectum. It is associatred with presence of blood and mucus in the stool, diarrhea and anemia. characteristically, CD involves entire mgastrointestinal tract, from the mouth to the anus. In CD, the inflammatory infiltrate involves the entire intestinal wall. Clinically manifested by abdominal pain, diarrhea, loss of appetite and weight loss. The complications are stenosis, fistulas, abscesses, and perianal involvement. In IBD TNF_alpha and proinflammatory cytokines are overexpressed. The analysis of the scientific literature shows that fertility, in pregant women suffering from IBD, is preserved. It shows slightly reduced for CD and ileo-anal pouch. Women with active disease at the time of conception have an increased risk of spontaneous abortion, preterm birth, with low birth weight and congenital malformations of the fetus. The indications for surgical treatment are the same as for non-pregnant women. The inactive disease or ileo-anal pouch is not a contraindication to spontaneous vaginal delivery, as is happens in the case of active colitis or perirectal fistulas or rectovaginal fistulas. Safe drug during pregnancy are: 5-aminosalicylic acid (5-ASA), steroids, 6-Mercaptopurine (&MP), Atatioprine (AZA) and Infliximab. Contraindicateddrugs are Metrotrexate and Thalidomide. In conclusion, the expectations about pregnancy, in women affected of IBD, is similar to the general population, especiually if the conception occurs in inactive phase of the disease

    Well-being among Italian medical oncologists: An exploratory study

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    none12noBackground: Recently, attention has been focused on physicians' stress and quality-of-life improvement. Due to their relationship with patients, oncologists in particular are overloaded physically, emotionally and psychologically. Previous studies showed that training of communication skills improves the satisfaction and well-being of physicians and patients. Aims: Our research investigates the relationship between work stress and engagement and personal well-being in physicians working in Italian hospitals. Materials and Methods: 176 physicians were included. Doctors filled out self-report questionnaires to evaluate work stress and coping strategies, personal well-being, work engagement and two purpose-built scales to measure the degree of perceived organizational support and the level of specific training of social and relational skills. Descriptive statistics were used to analyze data, as well as correlation analysis (Pearson's r), hierarchical regression analysis (enter step) and analysis of variance (one-way ANOVA). Result: Positive and significant correlations were found between variables. Moreover, physicians who obtained higher levels of specific training on social and relational skills reported lower levels of stress. Oncologists experienced greater stress than other physicians in terms of maladaptive coping and lack of additional training. Conclusions: The study suggests that physicians' well-being is mediated by professional aspects, such as social skills in relationships with patients. © 2014 S. Karger AG, Basel.openRusso A.; De Luca R.; Cicero G.; Civilleri A.; Bronte G.; Dispenza J.; Vieni S.; Guarneri R.; Cascio V.L.; Guadagna F.P.; Foddai E.; Pace F.Russo, A.; De Luca, R.; Cicero, G.; Civilleri, A.; Bronte, G.; Dispenza, J.; Vieni, S.; Guarneri, R.; Cascio, V. L.; Guadagna, F. P.; Foddai, E.; Pace, F
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