835 research outputs found
Un atlante fotografico interattivo delle specie arboree ed arbustive del giardino storico veneto
No full textPhytotoxicity and metal leaching in EDDS-assisted phytoextraction from pyrite wastes with Ethiopian mustard and fodder radish.
No full textThis study examines the influence of a low-persistent chelator (S,S-EDDS) on the growth of Ethiopian mustard ( Brassica carinata A. Braun) and fodder radish (Raphanus sativus L. var. oleiformis) and on metal leaching in As-Co-Pb-Zn contaminated pyrites wastes. Shoot biomass, leaf area and root biomass being more affected than lenght and electrical capacitance. EEDS generally improved shoot concentration of Cu, Co, Zn and Pb but repeated treatments caused significant metal leaching (mainly of Cu), explained by a multivariate relationship (R2= 0.52) including the integral over time of both leaf area (R2= 0.43) and root electrical capacitance (R2= 0.09). We conclude that roots play a secondary role in preventing metal leaching, because of the prevailing effect of leaf transpirationin cotrolling percolation. The best metal phytoextraction was achived with EDDS applied at harvest-a safe metal leaching strategy, expeciallyat the low dose of 2,5 mmol per kg of soil
Adaptive detection of distributed targets in compound-Gaussian noise without secondary data: A Bayesian approach
No full textIn this paper, we deal with the problem of adaptive detection of distributed targets embedded in colored noise modeled in terms of a compound-Gaussian process and without assuming that a set of secondary data is available.The covariance matrices of the data under test share a common structure while having different power levels. A Bayesian approach is proposed here, where the structure and possibly the power levels are assumed to be random, with appropriate distributions. Within this framework we propose GLRT-based and ad-hoc detectors. Some simulation studies are presented to illustrate the performances of the proposed algorithms. The analysis indicates that the Bayesian framework could be a viable means to alleviate the need for secondary data, a critical issue in heterogeneous scenarios
Heterogeneous Class Size Effects: New Evidence from a Panel of University Students
No full textUsing administrative records from a UK university, we present evidence on the effects of class size on students' test scores. We estimate non-linear class size effects controlling for unobserved heterogen-eity of students and faculty. We find that: (i) at the average class size, the effect size is -0.108; (ii) the effect size is negative and significant only for the smallest and largest ranges of class sizes and zero in intermediate class sizes; (iii) students at the top of the test score distribution are more affected by changes in class size, especially when class sizes are very large. © The Author(s). Journal compilation © Royal Economic Society 2010
Le popolazioni di Erysiphe necator
No full textCapitolo 4 in sintesi
• Gli studi genetici sulle popolazioni di E. necator hanno ricevuto un grande impulso a partire dalla metà degli anni ‘90;
• Diversi studi hanno portato alla definizione di una “teoria dei biotipi”, che inizialmente distingueva un genotipo “I” (corrispondente a un biotipo germogli a bandiera) e di un genotipo “III” (corrispondente a un biotipo ascospore), morfologicamente indistinguibili, sessualmente incompatibili e caratterizzati da un diverso comportamento epidemico;
• Successivi studi hanno permesso di classificare le linee clonali in due gruppi (A e B), il primo caratterizzato da una minore variabilità rispetto al secondo e da svernamento come micelio nelle gemme anziché come cleistotecio;
• Ricerche condotte sia in Italia che in altre zone viticole hanno ottenuto risultanti contrastanti con la teoria dei biotipi;
• In Emilia-Romagna è stata dimostrata la presenza prevalente di isolati del genotipo B, la capacità di tutti gli isolati di causare germogli bandiera e la non specificità dei genotipi rispetto alla modalità di svernamento
Discovery of a New Class of Highly Potent Inhibitors of Acid Ceramidase: Synthesis and Structure-Activity Relationship (SAR).
No full textAcid ceramidase (AC) is an intracellular cysteine amidase that catalyzes the hydrolysis of the lipid messenger ceramide. By regulating ceramide levels in cells, AC may contribute to the regulation of cancer cell proliferation and senescence and to the response to cancer therapy. We recently identified the antitumoral agent carmofur (4a) as the first nanomolar inhibitor of intracellular AC activity (rat AC, IC50 = 0.029 μM). In the present work, we expanded our initial structure-activity relationship (SAR) studies around 4a by synthesizing and testing a series of 2,4-dioxopyrimidine-1-carboxamides. Our investigations provided a first elucidation of the structural features of uracil derivatives that are critical for AC inhibition and led us to identify the first single-digit nanomolar inhibitors of this enzyme. The present results confirm that substituted 2,4-dioxopyrimidine-1-carboxamides are a novel class of potent inhibitors of AC. Selected compounds of this class may represent useful probes to further characterize the functional roles of AC
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