Search results for "RINGS"
showing 10 items of 434 documents
High Gradient Performance of an S-Band Backward Traveling Wave Accelerating Structure for Medical Hadron Therapy Accelerators
2018
The high-gradient performance of an accelerating structure prototype for a medical proton linac is presented. The structure was designed and built using technology developed by the CLIC collaboration and the target application is the TULIP (Turning Linac for Proton therapy) proposal developed by the TERA foundation. The special feature of this design is to produce gradient of more than 50 MV /m in low-β accelerating structures (v/c=0.38). The structure was tested in an S-band test stand at CERN. During the tests, the structure reached over above 60 MV/m at 1.2 μs pulse length and breakdown rate of about 5x10⁻⁶ bpp. The results presented include ultimate performance, long term behaviour and …
Integrated biomonitoring of airborne pollutants over space and time using tree rings, bark, leaves and epiphytic lichens
2016
The integrated use of tree rings and outer tissues, and lichens, was tested for monitoring how pollutant concentrations vary in space and over time nearby an incinerator in industrial area in Central Italy. Trace elements in thalli of lichen Xanthoria parietina and in leaves, bark, wood of Quercus pubescens, as well as carbon, oxygen and nitrogen isotope ratios in tree rings were analyzed. Some trace elements in the leaves differed significantly between the plots, though this was not the case in lichens and bark. The values of δ13C and δ18O showed the same trend in all plots, while the values of δ15N were higher in the distal plot. The results indicated that trace elements were intercepted …
New tree-ring evidence for the Late Glacial period from the northern pre-Alps in eastern Switzerland
2018
Abstract The rate and magnitude of temperature variability at the transition from the Last Glacial Maximum into the early Holocene represents a natural analog to current and predicted climate change. A limited number of high-resolution proxy archives, however, challenges our understanding of environmental conditions during this period. Here, we present combined dendrochronological and radiocarbon evidence from 253 newly discovered subfossil pine stumps from Zurich, Switzerland. The individual trees reveal ages of 41–506 years and were growing between the Allerod and Preboreal (∼13′900–11′300 cal BP). Together with previously collected pines from this region, this world's best preserved Late…
Activation of the plant plasma membrane H+ -ATPase. Is there a direct interaction between lysophosphatidylcholine and the C-terminal part of the enzy…
1996
The antagonistic effects of the fungal toxin beticolin-1 and of L-alpha-lysophosphatidylcholine (lysoPC) were investigated on the plasma membrane H+-ATPase of the plant Arabidopsis thaliana (isoform 2) expressed in yeast, using both wild-type enzyme (AHA2) and C-terminal truncated enzyme (aha2delta92). Phosphohydrolytic activities of both enzymes were inhibited by beticolin-1, with very similar 50% inhibitory concentrations, indicating that the toxin action does not involve the C-terminal located autoinhibitory domain of the proton pump. Egg lysoPC, a compound that activates the H+-ATPase by a mechanism involving the C-terminal part of the protein, was found to be able to reverse the inhibi…
Magnesium ions promote assembly of channel-like structures from beticolin 0, a non-peptide fungal toxin purified from Cercospora beticola.
1998
Beticolins are toxins produced by the fungus Cercospora beticola. Using beticolin 0 (B0), we have produced a strong and Mg(2+)-dependent increase in the membrane conductance of Arabidopsis protoplasts and Xenopus oocytes. In protein-free artificial bilayers, discrete deflexions of current were observed (12 pS unitary conductance in symmetrical 100 mM KCl) in the presence of B0 (approximately 10 microM) and in the presence of nominal Mg2+. Addition of 50 microM Mg2+ induced a macroscopic current which could be reversed to single channel current by chelating Mg2+ with EDTA. Both unitary and macroscopic currents were ohmic. The increase in conductance of biological membranes triggered by B0 is…
Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate
2019
Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic…
Nicodemia madagascariensis(Lam.) R. Parker (Family Scrophulariaceae), a casual alien plant new to Italy
2016
In this note the authors report the first case of naturalization of the Malagasy smoke bush within Italian territory. Along with a description of the abiotic and biotic characteristics of the invaded site, the current demographic and dynamic trends of the detected population by means of growth-ring analysis was also assessed. Moreover, an overview on the history of its introduction in Europe is provided, underlining the key role played by the Mediterranean cities with respect to the acclimatization and spread of alien tropical and subtropical plants. Due to its low frequency under cultivation, the Malagasy smoke bush should not behave as an invader in the future; on the other hand, its abil…
Ecological and conceptual consequences of Arctic pollution
2020
Although the effect of pollution on forest health and decline received much attention in the 1980s, it has not been considered to explain the ‘Divergence Problem’ in dendroclimatology; a decoupling of tree growth from rising air temperatures since the 1970s. Here we use physical and biogeochemical measurements of hundreds of living and dead conifers to reconstruct the impact of heavy industrialisation around Norilsk in northern Siberia. Moreover, we develop a forward model with surface irradiance forcing to quantify long‐distance effects of anthropogenic emissions on the functioning and productivity of Siberia’s taiga. Downwind from the world’s most polluted Arctic region, tree mortality ra…
Interannual memory effects for spring NDVI in semi-arid South Africa
2008
[1] Almost 20 years of Normalized Difference Vegetative Index (NDVI) and precipitation (PPT) data are analysed to better understand the interannual memory effects on vegetation dynamics observed at regional scales in Southern Africa (SA). The study focuses on a semi-arid region (25°S–31°S; 21°E–26°E) during the austral early summer (September–December). The memory effects are examined using simple statistical approaches (linear correlations and regressions) which require the definition of an early summer vegetation predictand (December NDVI minus September NDVI) and a consistent set of potential predictors (rainfall amount, number of rainy days, rainfall intensity, NDVI and Rain-Use-Efficie…
Statistical modelling and RCS detrending methods provide similar estimates of long-term trend in radial growth of common beech in north-eastern France
2011
International audience; Dendrochronological methods have greatly contributed to the documentation of past long-term trends in forest growth. These methods primarily focus on the high-frequency signals of tree ring chronologies. They require the removal of the ageing trend in tree growth, known as 'standardisation' or 'detrending', as a prerequisite to the estimation of such trends. Because the approach is sequential, it may however absorb part of the low-frequency historical signal. In this study, we investigate the effect of a sequential and a simultaneous estimation of the ageing trend on the chronology of growth. We formerly developed a method to estimate historical changes in growth, in…