664 research outputs found

    Evaluation of the quality and antioxidant capacity of woodland strawberry biotypes in Sicily

    Get PDF
    In Sicily, the woodland strawberry grows wild in forest glades in the Madonie and Nebrodi mountains and on Mount Etna. In this region, the main cultivated clone is Fragolina di Ribera, named after the towns where the crop originally developed. The cultivated woodland strawberry is different from its wild counterparts not only in vegetative vigour and size, but also in organoleptic quality. Fragolina di Ribera has always been described with sensory analysis as one of the best Sicilian berry. This study was carried out in Sicily and compared two June-bearing Fragaria vesca: Fragolina di Ribera and Fragolina di Maletto, and an everbearing variety Regina delle Valli, in order to determine the production, quality and nutraceutical characteristics of the fruit. Research results provided useful, more detailed information on those fruit compounds with nutritional and health benefits and the June-bearing Fragolina di Ribera was found not only to produce highly sweet, bright red fruits, but also fruits with high antioxidant capacity and high ascorbic acid, polyphenol and anthocyanin levels

    Characterization of iodine particles with Volatilization-Humidification Tandem Differential Mobility Analyser (VH-TDMA), Raman and SEM techniques

    Get PDF
    Particles formed upon photo-oxidation of CH2I2 and particles of I2O5 and HIO3 have been studied using a Volatilisation and Humidification Tandem Differential Mobility Analyser (VH-TDMA) system. Volatilization and hygroscopic behaviour have been investigated as function of temperature (from 25 to 400 degrees Celsius), humidity (RH from 80 to 98%), initial aerosol sizes (from 27 to 100 nm mobility diameter) and in nitrogen or air as the sheath gasses. The volatility behaviour of particles formed upon photo-oxidation of CH2I2 is more similar to that of HIO3 particles in a filtered sheath air than in nitrogen, with the particle shrinkage occurring at 190 degrees Celsius and accompanied by hygroscopic growth. Despite its high solubility, HIO3 was found not to be hygroscopic at room temperature with no significant growth displayed until the thermodenuder temperature reached 200 degrees Celsius or above when the particles have transformed into I2O5. Diiodopentaoxide (I2O5) particles exhibit relatively low hygroscopic growth factors of 1.2-2 in the humidity range investigated. Scanning Electron Microscopy (SEM) of particles formed upon photo-oxidation of CH2I2 shows that their primary elemental components were iodine and oxygen in a stoichiometric ratio of approximately 1:2 with 10% error. Both Raman spectra and SEM show poor crystallinity for all the aerosols produced

    Universal relation between Green's functions in random matrix theory

    Full text link
    We prove that in random matrix theory there exists a universal relation between the one-point Green's function GG and the connected two- point Green's function GcG_c given by \vfill N^2 G_c(z,w) = {\part^2 \over \part z \part w} \log (({G(z)- G(w) \over z -w}) + {\rm {irrelevant \ factorized \ terms.}} This relation is universal in the sense that it does not depend on the probability distribution of the random matrices for a broad class of distributions, even though GG is known to depend on the probability distribution in detail. The universality discussed here represents a different statement than the universality we discovered a couple of years ago, which states that a2Gc(az,aw)a^2 G_c(az, aw) is independent of the probability distribution, where aa denotes the width of the spectrum and depends sensitively on the probability distribution. It is shown that the universality proved here also holds for the more general problem of a Hamiltonian consisting of the sum of a deterministic term and a random term analyzed perturbatively by Br\'ezin, Hikami, and Zee.Comment: 34 pages, macros appended (shorts, defs, boldchar), hard figures or PICT figure files available from: [email protected]

    Correlations between eigenvalues of large random matrices with independent entries

    Full text link
    We derive the connected correlation functions for eigenvalues of large Hermitian random matrices with independently distributed elements using both a diagrammatic and a renormalization group (RG) inspired approach. With the diagrammatic method we obtain a general form for the one, two and three-point connected Green function for this class of ensembles when matrix elements are identically distributed, and then discuss the derivation of higher order functions by the same approach. Using the RG approach we re-derive the one and two-point Green functions and show they are unchanged by choosing certain ensembles with non-identically distributed elements. Throughout, we compare the Green functions we obtain to those from the class of ensembles with unitary invariant distributions and discuss universality in both ensemble classes.Comment: 23 pages, RevTex, hard figures available from [email protected]

    Contraceptive methods and knowledge of sexually transmitted diseases in nursing students. Results from a survey conducted at the University of Palermo

    Get PDF
    Background: The main purpose of the study was to evaluatesexual habits, sexual relations and knowledge of sexually transmitted infections (STIs) among the students in the nursing science course of University of Palermo, and to evaluate the use of contraceptive methods.Methods: In April 2019, a survey was provided to students who attend daily lessons in the nursing science course of University of Palermo, that investigate primarily about sexual habits, sexual relations and knowledge of sexually transmitted diseases. A multivariable logistic regression was performed.Results: The sample size consists of 405 students. The average age of the sample is 21.65 years, 69.63% of the interviewees are women. In relation to the question "Do you think you are sufficiently informed to be able to avoid risks of infection from sexually transmitted diseases? No", the analysis shows that this independent variable is significantly associated with the following independent variables: female gender (aOR 3.11, 95% CI 1.01 - 9.65); "how would you define your knowledge about contraceptive methods? - Poor" (aOR 5.38, 95% CI 1.79 - 16.20); "have you ever received information on sex education and/or sexually transmitted diseases? - No" (aOR 11.59, 95% CI 2.26 - 59.42); "do you know the human papillomavirus (HPV) vaccination? - yes, but I'm not vaccinated" (aOR 3.09, 95% CI 1.12 - 8.51); "do you know that men can also undergo HPV vaccination? - No" (aOR 2.67, 95% CI 1.01 - 7.04).Conclusion: Based on our findings, it is necessary to implement sexual education programs for the improvement of knowledge in terms of STIs and the promotion of health. Improving sexual health outcomes for young people is a priority for the public health

    Hall Anomaly and Vortex-Lattice Melting in Superconducting Single Crystal YBa2Cu3O7-d

    Full text link
    Sub-nanovolt resolution longitudinal and Hall voltages are measured in an ultra pure YBa2Cu3O7-d single crystal. The Hall anomaly and the first-order vortex-lattice melting transition are observed simultaneously. Changes in the dynamic behavior of the vortex solid and liquid are correlated with features of the Hall conductivity sxy. With the magnetic field oriented at an angle from the twin-boundaries, the Hall conductivity sharply decreases toward large negative values at the vortex-lattice melting transition.Comment: 6 pages, 2 figures included, Postscript, to appear in Phys. Rev. Let

    Renormalizing Rectangles and Other Topics in Random Matrix Theory

    Full text link
    We consider random Hermitian matrices made of complex or real M×NM\times N rectangular blocks, where the blocks are drawn from various ensembles. These matrices have NN pairs of opposite real nonvanishing eigenvalues, as well as M−NM-N zero eigenvalues (for M>NM>N.) These zero eigenvalues are ``kinematical" in the sense that they are independent of randomness. We study the eigenvalue distribution of these matrices to leading order in the large N,MN,M limit, in which the ``rectangularity" r=MNr={M\over N} is held fixed. We apply a variety of methods in our study. We study Gaussian ensembles by a simple diagrammatic method, by the Dyson gas approach, and by a generalization of the Kazakov method. These methods make use of the invariance of such ensembles under the action of symmetry groups. The more complicated Wigner ensemble, which does not enjoy such symmetry properties, is studied by large NN renormalization techniques. In addition to the kinematical δ\delta-function spike in the eigenvalue density which corresponds to zero eigenvalues, we find for both types of ensembles that if ∣r−1∣|r-1| is held fixed as N→∞N\rightarrow\infty, the NN non-zero eigenvalues give rise to two separated lobes that are located symmetrically with respect to the origin. This separation arises because the non-zero eigenvalues are repelled macroscopically from the origin. Finally, we study the oscillatory behavior of the eigenvalue distribution near the endpoints of the lobes, a behavior governed by Airy functions. As r→1r\rightarrow 1 the lobes come closer, and the Airy oscillatory behavior near the endpoints that are close to zero breaks down. We interpret this breakdown as a signal that r→1r\rightarrow 1 drives a cross over to the oscillation governed by Bessel functions near the origin for matrices made of square blocks.Comment: LateX, 34 pages, 3 ps figure
    • …
    corecore