206 research outputs found

    Developing Intensity-Duration-Frequency (IDF) Curves From Satellite-Based Precipitation: Methodology and Evaluation

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    Given the continuous advancement in the retrieval of precipitation from satellites, it is important to develop methods that incorporate satellite-based precipitation data sets in the design and planning of infrastructure. This is because in many regions around the world, in situ rainfall observations are sparse and have insufficient record length. A handful of studies examined the use of satellite-based precipitation to develop intensity-duration-frequency (IDF) curves; however, they have mostly focused on small spatial domains and relied on combining satellite-based with ground-based precipitation data sets. In this study, we explore this issue by providing a methodological framework with the potential to be applied in ungauged regions. This framework is based on accounting for the characteristics of satellite-based precipitation products, namely, adjustment of bias and transformation of areal to point rainfall. The latter method is based on previous studies on the reverse transformation (point to areal) commonly used to obtain catchment-scale IDF curves. The paper proceeds by applying this framework to develop IDF curves over the contiguous United States (CONUS); the data set used is Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks – Climate Data Record (PERSIANN-CDR). IDFs are then evaluated against National Oceanic and Atmospheric Administration (NOAA) Atlas 14 to provide a quantitative estimate of their accuracy. Results show that median errors are in the range of (17–22%), (6–12%), and (3–8%) for one-day, two-day and three-day IDFs, respectively, and return periods in the range (2–100) years. Furthermore, a considerable percentage of satellite-based IDFs lie within the confidence interval of NOAA Atlas 14

    Genetic variation within the olive (Olea europaea L.) cultivar Oblica detected using amplified fragment length polymorphism (AFLP) markers

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    Oblica is the predominant olive cultivar in Croatia, spread widely in all the olive growing regions. Morphological variability within the cultivar is well documented but often it has been attributed to environmental factors rather than to genetic ones. In order to investigate intracultivar variability on the molecular level, olive samples from 4 growing regions in Croatia (South  Dalmatia, Middle Dalmatia, Kvarner islands and Iner Dalmatia) were screened for amplified fragment length polymorphisms (AFLP). DNA was extracted from leaf tissue and 9 AFLP primer combinations were used. Genetic distancesbetween individual trees were calculated using Dice similarity coefficient and the dendrogram based on UPGMA cluster analysis was constructed. Preliminary results of AFLP analysis indicate that the cultivar Oblica can be regarded as mixture of clonal variants

    The Energy Operator for a Model with a Multiparametric Infinite Statistics

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    In this paper we consider energy operator (a free Hamiltonian), in the second-quantized approach, for the multiparameter quon algebras: aiajqijajai=δij,i,jIa_{i}a_{j}^{\dagger}-q_{ij}a_{j}^{\dagger}a_{i} = \delta_{ij}, i,j\in I with (qij)i,jI(q_{ij})_{i,j\in I} any hermitian matrix of deformation parameters. We obtain an elegant formula for normally ordered (sometimes called Wick-ordered) series expansions of number operators (which determine a free Hamiltonian). As a main result (see Theorem 1) we prove that the number operators are given, with respect to a basis formed by "generalized Lie elements", by certain normally ordered quadratic expressions with coefficients given precisely by the entries of the inverses of Gram matrices of multiparticle weight spaces. (This settles a conjecture of two of the authors (S.M and A.P), stated in [8]). These Gram matrices are hermitian generalizations of the Varchenko's matrices, associated to a quantum (symmetric) bilinear form of diagonal arrangements of hyperplanes (see [12]). The solution of the inversion problem of such matrices in [9] (Theorem 2.2.17), leads to an effective formula for the number operators studied in this paper. The one parameter case, in the monomial basis, was studied by Zagier [15], Stanciu [11] and M{\o}ller [6].Comment: 24 pages. accepted in J. Phys. A. Math. Ge

    A New Deformed Supersymmetric Oscillator

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    We construct and discuss the Fock-space representation for a deformed oscillator with "peculiar" statistics. We show that corresponding algebra represents deformed supersymmetric oscillator.Comment: LATEX, 10 pages, no figures, to appear in Europhys.Let

    Molecular identification of a phytoplasma infecting grapevine in the Republic of Macedonia

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    Phytoplasmas from the ribosomal subgroup 16SrXII-A (stolbur) were identified by PCR and RFLP analyses of 16S rRNA gene and elongation factor-Tu phytoplasma gene (tuf) in symptomatic grapevines from the Veles and Skopje areas in Macedonia. Two methods were used for nucleic acid extraction. Amplification and RFLP results of 16S rDNA were not influenced by the method used, but RFLP patterns of tuf gene revealed additional bands if a less time consuming method was applied. The possible origin of these bands is discussed. This is the first report of the presence of the stolbur phytoplasma in cvs Chardonnay and Vranac in Macedonia.

    On the R-Matrix Formulation of Deformed Algebras and Generalized Jordan-Wigner Transformations

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    The deformed algebra A(R)\cal{A(R)}, depending upon a Yang-Baxter R- matrix, is considered. The conditions under which the algebra is associative are discussed for a general number of oscillators. Four types of solutions satisfying these conditions are constructed and two of them can be represented by generalized Jordan-Wigner transformations.Our analysis is in some sense an extension of the boson realization of fermions from single-mode to multimode oscillators.Comment: 10+ii pages,preprint RBI-TH-10/93,Latex,(to appear in Europhys.Lett.

    The isolation, analytical characterization by HPLC-UV and NMR spectroscopy, cytotoxic and antioxidant activities of baeomycesic acid from Thamnolia vermicularis var. subuliformis

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    The aim of this work was the analytical characterization of the β-orcinol depside, baeomycesic acid in lichens extracts. The extract of Thamnolia vermicularis var. subuliformis was analyzed by the two different methods, namely HPLC-UV and 1H NMR analysis. The results showed that baeomycesic acid was the most abundant depside in the lichens. These results could be of use for rapid identification of this metabolite in other lichen species. Besides baeomycesic acid, three depsides and one monocyclic phenolic compound were isolated from the lichen extract on the chromatographic column. The structure of baeomycesic acid was confirmed by HPLC-UV and spectroscopic methods. In addition, antioxidant and cytotoxic activities of baeomycesic acid were determined. The result of the testing showed that baeomycesic acid exhibited a moderate radical scavenging activity (IC50 = 602.10 ± 0.54 μg/mL) and good cytotoxic activity. This is the first report of detailed analytical characterization, isolation, as well as antioxidant and cytotoxic activities of baeomycesic acid from Thamnolia vermicularis. These results may be helpful in future industrial production of herbal medicines that include this important natural product

    Survey of phenolic compounds and sensorial profile of Dalmatian virgin olive oils

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    Fenolni spojevi su prirodni antioksidansi prisutni u djevičanskom maslinovom ulju (DMU) koji utječu na konačnu procjenu kvalitete pojedinog maslinovog ulja. To su bioaktivni spojevi koji imaju izraženu antioksidacijsku aktivnost i značajno utječu na oksidacijsku stabilnost DMU, ali i na njegova senzorska svojstva. U ovom radu ispitivan je sastav fenola u djevičanskim maslinovim uljima iz odabranih autohtonih hrvatskih sorta s nekoliko lokacija na području srednje Dalmacije. Trogodišnja istraživanja provedena su na sortnim uljima dobivenim istovjetnim tehnološkim postupkom prerade. Provedeno je i senzorsko ocjenjivanje sortnih DMU kojima su definirana specifična obilježja okusa i arome koja se pripisuju isključivo sorti. U preliminarnim istraživanjima određeni su osnovni parametri kvalitete prema propisima za ekstra djevičansko maslinovo ulje, kao i ukupni udjel fenolnih tvari te sastav pojedinačnih fenola za pojedino sortno ulje. Kod nekih sorti su pojedine grupe fenolnih spojeva (sekoiridoidi, flavoni, lignani) pokazale veću antioksidacijsku aktivnost nego ukupni fenoli. Kod ulja drugih sorti, oksidacijska stabilnost ovisi upravo o udjelu ukupnih fenola. Kod svih ispitivanih uzoraka u ovom istraživanju vrlo je dobar udjel fenola i različitih sastava pojedinačnih fenolnih spojeva, ovisno o sorti. Senzorske karakteristike razlikuju se kod uzoraka ulja ovisno o ishodnoj sorti i imaju određena svojstva za svako pojedino sortno ulje.Phenolic compounds are natural antioxidants present in virgin olive oil (VOO) that influence the final assessment of the quality of certain olive oil. These are the bioactive compounds that have a pronounced antioxidant activity and significantly affect the oxidative stability of the VOO, but also its sensorial properties. This paper examined the composition of phenolic compounds in VOO\u27s from selected indigenous Croatian varieties from several locations in central Dalmatia. A three-year study was conducted on varietal oils obtained by identical chemical processing procedure. Sensory evaluation of monovarietal VOO’s was also conducted and specific characteristics of taste and aroma due to the olive variety were defined. In preliminary research, the basic quality parameters were determined according to the regulations for the extra virgin olive oil, as well as the total phenol content and the composition of individual phenolic compounds for particular monovarietal oils. Some varieties showed that a particular group of phenols (secoiridoided, flavones, lignans) had higher antioxidant activity than total phenols. In oils from other olive varieties, oxidative stability depended on the proportion of total phenols. In all samples in this study very good total phenol content was detected as well as different composition of individual phenolic compounds, depending on the olive cultivar. Sensorial characteristics of the samples varied depending on the variety and had specific attributes for each monovarietal VOO

    Survey of phenolic compounds and sensorial profile of Dalmatian virgin olive oils

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    Fenolni spojevi su prirodni antioksidansi prisutni u djevičanskom maslinovom ulju (DMU) koji utječu na konačnu procjenu kvalitete pojedinog maslinovog ulja. To su bioaktivni spojevi koji imaju izraženu antioksidacijsku aktivnost i značajno utječu na oksidacijsku stabilnost DMU, ali i na njegova senzorska svojstva. U ovom radu ispitivan je sastav fenola u djevičanskim maslinovim uljima iz odabranih autohtonih hrvatskih sorta s nekoliko lokacija na području srednje Dalmacije. Trogodišnja istraživanja provedena su na sortnim uljima dobivenim istovjetnim tehnološkim postupkom prerade. Provedeno je i senzorsko ocjenjivanje sortnih DMU kojima su definirana specifična obilježja okusa i arome koja se pripisuju isključivo sorti. U preliminarnim istraživanjima određeni su osnovni parametri kvalitete prema propisima za ekstra djevičansko maslinovo ulje, kao i ukupni udjel fenolnih tvari te sastav pojedinačnih fenola za pojedino sortno ulje. Kod nekih sorti su pojedine grupe fenolnih spojeva (sekoiridoidi, flavoni, lignani) pokazale veću antioksidacijsku aktivnost nego ukupni fenoli. Kod ulja drugih sorti, oksidacijska stabilnost ovisi upravo o udjelu ukupnih fenola. Kod svih ispitivanih uzoraka u ovom istraživanju vrlo je dobar udjel fenola i različitih sastava pojedinačnih fenolnih spojeva, ovisno o sorti. Senzorske karakteristike razlikuju se kod uzoraka ulja ovisno o ishodnoj sorti i imaju određena svojstva za svako pojedino sortno ulje.Phenolic compounds are natural antioxidants present in virgin olive oil (VOO) that influence the final assessment of the quality of certain olive oil. These are the bioactive compounds that have a pronounced antioxidant activity and significantly affect the oxidative stability of the VOO, but also its sensorial properties. This paper examined the composition of phenolic compounds in VOO\u27s from selected indigenous Croatian varieties from several locations in central Dalmatia. A three-year study was conducted on varietal oils obtained by identical chemical processing procedure. Sensory evaluation of monovarietal VOO’s was also conducted and specific characteristics of taste and aroma due to the olive variety were defined. In preliminary research, the basic quality parameters were determined according to the regulations for the extra virgin olive oil, as well as the total phenol content and the composition of individual phenolic compounds for particular monovarietal oils. Some varieties showed that a particular group of phenols (secoiridoided, flavones, lignans) had higher antioxidant activity than total phenols. In oils from other olive varieties, oxidative stability depended on the proportion of total phenols. In all samples in this study very good total phenol content was detected as well as different composition of individual phenolic compounds, depending on the olive cultivar. Sensorial characteristics of the samples varied depending on the variety and had specific attributes for each monovarietal VOO

    Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones

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    Indications exist that paramagnetic calcium phosphates may be able to promote regeneration of bone faster than their regular, diamagnetic counterparts. In this study, analyzed was the influence of paramagnetic cobalt-substituted hydroxyapatite nanoparticles on osteoporotic alveolar bone regeneration in rats. Simultaneously, biocompatibility of the material was tested in vitro, on osteoblastic MC3T3-E1 and epithelial Caco-2 cells in culture. The material was shown to be biocompatible and nontoxic when added to epithelial monolayers in vitro, while it caused a substantial decrease in the cell viability as well as deformation of the cytoskeleton and cell morphology when incubated with the osteoblastic cells. In the course of 6 months after the implantation of the material containing different amounts of cobalt, ranging from 5 to 12 wt%, in the osteoporotic alveolar bone of the lower jaw, the following parameters were investigated: histopathological parameters, alkaline phosphatase and alveolar bone density. The best result in terms of osteoporotic bone tissue regeneration was observed for hydroxyapatite nanoparticles with the largest content of cobalt ions. The histological analysis showed a high level of reparatory ability of the nanoparticulate material implanted in the bone defect, paralleled by a corresponding increase in the alveolar bone density. The combined effect of growth factors from autologous plasma admixed to cobalt-substituted hydroxyapatite was furthermore shown to have a crucial effect on the augmented osteoporotic bone regeneration upon the implantation of the biomaterial investigated in this study.This is accepted peer-reviewed version of the article: Ignjatović, N., Ajduković, Z., Savić, V., Najman, S., Mihailović, D., Vasiljević, P., ... & Uskoković, D. (2013). Nanoparticles of cobalt-substituted hydroxyapatite in regeneration of mandibular osteoporotic bones. Journal of Materials Science: Materials in Medicine, 24(2), 343-354. [https://dx.doi.org/10.1007/s10856-012-4793-1]Published version: [https://vinar.vin.bg.ac.rs/handle/123456789/7410
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