812 research outputs found

    Application of genetic markers to the discrimination of European Black Poplar ( Populus nigra ) from American Black Poplar ( P. deltoides ) and Hybrid Poplars ( P. x canadensis ) in Switzerland

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    European Black Poplar (Populus nigra) is considered a rare and endangered tree species because of severe reduction of its natural riverine habitat and potential hybridisation with the related non-indigenous taxa P. deltoides and P. x canadensis. As it is difficult to distinguish these taxa solely based on their morphology, we applied a PCR-based assay with an easy-to-use and robust molecular marker set (cpDNA trnL-trnF/RsaI RFLP, nDNA win3 and nDNA POPX/MspI RFLP) in order to identify pure P. nigra. Different plant tissues could be used for fast and standardised DNA extraction. The application of the three marker types was tested on a number of different Populus taxa, and they were also used for the verification of pure P. nigra in a sample of 304 putative P. nigra individuals from Switzerland. Cross-checking of the DNA data with those using a traditional allozyme approach resulted in complete agreement. The availability of molecular identification methods is an important prerequisite for the conservation of European Black Poplar, because pure, non-introgressed plant material can then be used in restoration projects of European floodplain

    Search for Neutron Flux Generation in a Plasma Discharge Electrolytic Cell

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    Following some recent unexpected hints of neutron production in setups like high-voltage atmospheric discharges and plasma discharges in electrolytic cells, we present a measurement of the neutron flux in a configuration similar to the latter. We use two different types of neutron detectors, poly-allyl-diglicol-carbonate (PADC, aka CR-39) tracers and Indium disks. At 95% C.L. we provide an upper limit of 1.5 neutrons cm^-2 s^-1 for the thermal neutron flux at ~5 cm from the center of the cell. Allowing for a higher energy neutron component the largest allowed flux is 64 neutrons cm^-2 s^-1. This upper limit is two orders of magnitude smaller than what previously claimed in an electrolytic cell plasma discharge experiment. Furthermore the behavior of the CR-39 is discussed to point our possible sources of spurious signals.Comment: 4 pages, 3 figure

    Dimensional reduction of the Dirac equation in arbitrary spatial dimensions

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    We investigate the general properties of the dimensional reduction of the Dirac theory, formulated in a Minkowski spacetime with an arbitrary number of spatial dimensions. This is done by applying Hadamard’s method of descent, which consists in conceiving low-dimensional theories as a specialization of high-dimensional ones that are uniform along the additional space coordinate. We show that the Dirac equation reduces to either a single Dirac equation or two decoupled Dirac equations, depending on whether the higher-dimensional manifold has even or odd spatial dimensions, respectively. Furthermore, we construct and discuss an explicit hierarchy of representations in which this procedure becomes manifest and can easily be iterated

    Ductopenia and fetal liver-like architecture as unique and evocative sign of Turner syndrome

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    Abstract. -BACKGROUND: Turner syndrome is the most common genetic disorder in females. In most subjects, with a normal physical appearance at birth, the diagnosis is suspected long after birth because of short stature, delayed puberty, primary or secondary amenorrhea or infertility. Abnormalities of liver function tests are reported in literature, with a prevalence ranging from 20% to 80%. In most subjects liver diseases are selflimiting, associated with obesity, hormonal therapy and autoimmune diseases. An association between Turner syndrome and cryptogenic liver disease has been reported. Abnormalities of liver function tests could be the unique sign of Turner syndrome in subjects with normal phenotypes. The histological picture of "fetal liver-like architecture" and "ductopenia" is of fundamental importance for the diagnosis of chromosomopathy. AIM: Review the causes of hypertransaminasemia by focusing on more rare as metabolic and genetic diseases. MATERIALS AND METHODS: We evaluated a 10 year old girl with a normal phenotype affected by chronic hypertransaminasemia and cholestasis, in whom a needle liver biopsy was performed after the most common causes of hypertransaminasemia were excluded. RESULTS: Liver histological evaluation revealed a smoldering colangiopathy with mild ductopenia and a fetal liver-like architecture. Turner syndrome, suspected on the basis of this histological picture, was confirmed by a pelvic ultrasound and a chromosome analysis. CONCLUSIONS: The histological features of "fetal liver-like architecture" and "ductopenia" represent an evocative sign that could indicate the diagnostic suspicion of Turner syndrome in a subject lacking in signs or symptoms of this disease. It is important to perform a pelvic ultrasound and an endocrinological evaluation in all females with chronic asymptomatic hypertransaminasemia even though they have normal phenotypes

    Copper benchmark experiment for the testing of JEFF-3.2 nuclear data for fusion applications

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    A neutronics benchmark experiment on a pure Copper block (dimensions 60 × 70 × 70 cm3) aimed at testing and validating the recent nuclear data libraries for fusion applications was performed in the frame of the European Fusion Program at the 14 MeV ENEA Frascati Neutron Generator (FNG). Reaction rates, neutron flux spectra and doses were measured using different experimental techniques (e.g. activation foils techniques, NE213 scintillator and thermoluminescent detectors). This paper first summarizes the analyses of the experiment carried-out using the MCNP5 Monte Carlo code and the European JEFF-3.2 library. Large discrepancies between calculation (C) and experiment (E) were found for the reaction rates both in the high and low neutron energy range. The analysis was complemented by sensitivity/uncertainty analyses (S/U) using the deterministic and Monte Carlo SUSD3D and MCSEN codes, respectively. The S/U analyses enabled to identify the cross sections and energy ranges which are mostly affecting the calculated responses. The largest discrepancy among the C/E values was observed for the thermal (capture) reactions indicating severe deficiencies in the 63,65Cu capture and elastic cross sections at lower rather than at high energy. Deterministic and MC codes produced similar results. The 14 MeV copper experiment and its analysis thus calls for a revision of the JEFF-3.2 copper cross section and covariance data evaluation. A new analysis of the experiment was performed with the MCNP5 code using the revised JEFF-3.3-T2 library released by NEA and a new, not yet distributed, revised JEFF-3.2 Cu evaluation produced by KIT. A noticeable improvement of the C/E results was obtained with both new libraries
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