762 research outputs found

    SHORT CHARACTERIZATION OF PLANT SPECIES FROM CENTAUREA GENUS PRESENT IN ”AL. BELDIE” HERBARIUM FROM ”MARIN DRĂCEA” NATIONAL INSTITUTE FOR RESEARCH AND DEVELOPMENT IN FORESTRY - BUCHAREST

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    ”Al Beldie” herbarium from ”Marin Drăcea” National Institute for Research and Development in Forestry is an important herbarium with a significant role in the present research paper.This herbarium is ilisted in Index Herbaria and is composed of approximately 60.000 sheets with dried specimens of plants. From those 60.000 sheets, 71 belong to the genus Centaurea, with 19 species to be more precise. All of these species were collected by known personalities in the field of systematic botany, most of them being Romanian. The species were collected between 1855 and 1951 from the entire world, with a great majority from Romania. The aim of this article is to describe some species of Centaurea that are present in this herbarium. In this way it can be observed how important it is to collect, identify and preserve sheets with dried species in herbarium, given that these species of plants can be very hard to identify

    Serum selenium concentrations in patients with newly diagnosed lymphoid malignancies

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    Background. Increased mortality from lymphoid malignancies following exposure to environmental selenium has recently been reported, Moreover, conflicting results have been found in investigations examining the relationship between serum concentrations of selenium and some clinical features of malignant lymphoproliferative diseases. Methods, Serum concentrations of selenium were analyzed by atomic absorption spectrometry in fifty-nine patients with newly diagnosed chronic lymphoid malignancies and in forty control subjects. Results. Selenium concentrations were significantly lower in patients than in control subjects, However, when only patients with localized disease were compared to controls, no significant difference in serum selenium concentrations was observed. Clinical stage was inversely associated with selenium levels. High-grade non-Hodgkin's lymphoma was characterized by lower selenium levels than low-grade and intermediate-grade disease. Selenium levels were positively associated with albumin and hemoglobin, and inversely correlated with serum concentrations of beta 2-microglobulin and with erythrocyte sedimentation rate. Conclusions. The findings of this study do not suggest that a high selenium intake represents a risk factor for malignant lymphoproliferative diseases, but limitations of the investigation hamper evaluation of the results. The possible utility of determining serum concentrations of selenium in the clinical evaluation ofpatients with lymphoid malignancies merits examination in larger studies

    A SHORT DESCRIPTION OF SCORZONERA PLANT SPECIES PRESENT IN ALEXANDRU BELDIE HERBARIUM FROM I.N.C.D.S. BUCHAREST

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    The present paper reunites the morphological and ecological description of Scorzonera plant species present in the Al. Beldie Herbarium from Marin Drăcea National Institute for Research and Development in Forestry (INCDS) in Bucharest. Furthermore, this article organizes the herbarium exemplars based on species, harvest year, the place from where they were taken and the specialist that has gathered them. The first part of the article starts with a short description of the herbarium and its specific, followed by presenting the material and method used in elaborating the paper. As such, the material is represented by the 83 plates containing exemplars of some Scorzonera species. A very important aspect which must be specified is the fact that the herbarium has a significant number of rare endangered or endemic specimens. One example, the protect species Scorzonerarosea, is present in the herbarium with 26 plates that were mainly gathered in the year 1936 by Al. Beldie himself.  Another rare species, Scorzonera hispanica, is represented in 16 plates from within the herbarium and is of a high interest as it is the oldest species of the genre, being harvested in the year 1794. Beside the description of the gathered Scorzonera species, the present paper presents the gathering map of the species present in the herbarium at an European level, together with analyzing the gathering periods of these species. Some of the oldest gathered species are also presented in this article. The paper ends with some conclusions regarding the Scorzonera species’ analysis and exemplars present in the herbarium, while briefly presenting their most novel aspects and characteristics.

    Observing Nearby Nuclei on Paramagnetic Trityls and MOFs via DNP and Electron Decoupling

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    Dynamic nuclear polarization (DNP) is an NMR sensitivity enhancement technique that mediates polarization transfer from unpaired electrons to NMR-active nuclei. Despite its success in elucidating important structural information on biological and inorganic materials, the detailed polarization-transfer pathway from the electrons to the nearby and then the bulk solvent nuclei, and finally to the molecules of interest-remains unclear. In particular, the nuclei in the paramagnetic polarizing agent play significant roles in relaying the enhanced NMR polarizations to more remote nuclei. Despite their importance, the direct NMR observation of these nuclei is challenging because of poor sensitivity. Here, we show that a combined DNP and electron decoupling approach can facilitate direct NMR detection of these nuclei. We achieved an ∼80 % improvement in NMR intensity via electron decoupling at 0.35 T and 80 K on trityl radicals. Moreover, we recorded a DNP enhancement factor of urn:x-wiley:09476539:media:chem202202556:chem202202556-math-0001 ∼90 and ∼11 % higher NMR intensity using electron decoupling on paramagnetic metal-organic framework, magnesium hexaoxytriphenylene (MgHOTP MOF)

    Electron drift-mobility measurements in polycrystalline CuIn1-xGaxSe2 solar cells

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    We report photocarrier time-of-flight measurements of electron drift mobilities for the p-type CuIn1-xGaxSe2 films incorporated in solar cells. The electron mobilities range from 0.02 to 0.05 cm^2/Vs and are weakly temperature-dependent from 100–300 K. These values are lower than the range of electron Hall mobilities (2-1100 cm2/Vs) reported for n-type polycrystalline thin films and single crystals. We propose that the electron drift mobilities are properties of disorder-induced mobility edges and discuss how this disorder could increase cell efficiencies

    Two ways to be endemic. Alps and Apennines are different functional refugia during climatic cycles

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    Endemics co-occur because they evolved in situ and persist regionally or because they evolved ex situ and later dispersed to shared habitats, generating evolutionary or ecological endemicity centres, respectively. We investigate whether different endemicity centres can intertwine in the region ranging from Alps to Sicily, by studying their butterfly fauna. We gathered an extensive occurrence data set for butterflies of the study area (27,123 records, 269 species, in cells of 0.5 × 0.5 degrees of latitude-longitude). We applied molecular-based delimitation methods (GMYC model) to 26,557 cytochrome c oxidase subunit 1 (COI) sequences of Western Palearctic butterflies. We identified entities based on molecular delimitations and/or the checklist of European butterflies and objectively attributed occurrences to their most probable entity. We obtained a zoogeographic regionalisation based on the 69 endemics of the area. Using phylogenetic ANOVA we tested if endemics from different centres differ from each other and from nonendemics for key ecological traits and divergence time. Endemicity showed high incidence in the Alps and Southern Italy. The regionalisation separated the Alps from the Italian Peninsula and Sicily. The endemics of different centres showed a high turnover and differed in phylogenetic distances, phenology and distribution traits. Endemics are on average younger than nonendemics and the Peninsula-Sicily endemics also have lower variance in divergence than those from the Alps. The observed variation identifies Alpine endemics as paleoendemics, now occupying an ecological centre, and the Peninsula-Sicily ones as neoendemics, that diverged in the region since the Pleistocene. The results challenge the common view of the Alpine-Apennine area as a single “Italian refugium”

    Evolution of the E(1/21+)E(3/21+)E(1/2^+_1)-E(3/2^+_1) energy spacing in odd-mass K, Cl and P isotopes for N=2028N=20-28

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    The energy of the first excited state in the neutron-rich N=28 nucleus 45Cl has been established via in-beam gamma-ray spectroscopy following proton removal. This energy value completes the systematics of the E(1/2^+_1)-E(3/2^+_1) level spacing in odd-mass K, Cl and P isotopes for N=20-28. The results are discussed in the framework of shell-model calculations in the sd-fp model space. The contribution of the central, spin-orbit and tensor components is discussed from a calculation based on a proton single-hole spectrum from G-matrix and pi + rho meson exchange potentials. A composite model for the proton 0d_{3/2}-1s_{1/2} single-particle energy shift is presented.Comment: Phys. Rev. C, in pres

    Large scale shell model calculations for odd-odd 5862^{58-62}Mn isotopes

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    Large scale shell model calculations have been carried out for odd-odd 5862^{58-62}Mn isotopes in two different model spaces. First set of calculations have been carried out in full fp\it{fp} shell valence space with two recently derived fp\it{fp} shell interactions namely GXPF1A and KB3G treating 40^{40}Ca as core. The second set of calculations have been performed in fpg9/2{fpg_{9/2}} valence space with the fpgfpg interaction treating 48^{48}Ca as core and imposing a truncation by allowing up to a total of six particle excitations from the 0f7/2_{7/2} orbital to the upper fp\it{fp} orbitals for protons and from the upper fp\it{fp} orbitals to the 0g9/2_{9/2} orbital for neutron. For low-lying states in 58^{58}Mn, the KB3G and GXPF1A both predicts good results and for 60^{60}Mn, KB3G is much better than GXPF1A. For negative parity and high-spin positive parity states in both isotopes fpgfpg interaction is required. Experimental data on 62^{62}Mn is sparse and therefore it is not possible to make any definite conclusions. More experimental data on negative parity states is needed to ascertain the importance of 0g9/2_{9/2} and higher orbitals in neutron rich Mn isotopes.Comment: 5 pages, 4 figures, Submitted to Eur. Phys. J.

    Two-neutron knockout from neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si

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    Two-neutron knockout reactions from nuclei in the proximity of the proton dripline have been studied using intermediate-energy beams of neutron-deficient 34^{34}Ar, 30^{30}S, and 26^{26}Si. The inclusive cross sections, and also the partial cross sections for the population of individual bound final states of the 32^{32}Ar, 28^{28}S and 24^{24}Si knockout residues, have been determined using the combination of particle and γ\gamma-ray spectroscopy. Similar to the two-proton knockout mechanism on the neutron-rich side of the nuclear chart, these two-neutron removal reactions from already neutron-deficient nuclei are also shown to be consistent with a direct reaction mechanism.Comment: Phys. Rev. C, rapid communication, in pres

    The isolated Erebia pandrose Apennine population is genetically unique and endangered by climate change

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    Climate change is causing shifts in the distribution of many species and populations inhabiting mountain tops are particularly vulnerable to these threats because they are constrained in altitudinal shifts. Apennines are a relatively narrow and low mountain chain located in Southern Europe, which hosts many isolated populations of mountain species. The butterfly Erebia pandrose was recorded for the last time in the Apennines in 1977, on the top of a single massif (Monti della Laga). We confirmed the presence of a small, isolated population of E. pandrose in the Apennines, at a distance of more than 400 km to any other known populations. Then, we examined the cytochrome c oxidase subunit 1 mitochondrial DNA marker of this species across the Palaearctic area and estimated the potential decline over the Alps and the Apennines due to future climatic changes. The Apennine population represents an endemic lineage characterised by eight mutations over the 658 bp analysed (1.2%). In the Alps and Apennines, this species has shifted uphill more than 3 m per year since the end of the 19th century and more than 22 m per year since 1995. Species distribution models suggested that these mountain populations will experience a generalised loss of climatic suitability, which, according to our projections, could lead to the extinction of the Apennine population in a few decades. Erebia pandrose has the potential to become a flagship species for advertising the risk of losing unique fractions of genetic diversity for mountain species
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