4,194 research outputs found
Effects of increased autumn temperatures and sub-acute levels of ammonia on post-winter development of four cultivars of winter oilseed rape (Brassica napus L.)
Early planting dates, warm autumns and increased N mineralisationĀ rates may advance the growth of winter crops and also a high supply of nitrogen poses risks of excess biomass accumulation before the winter leading to reduced frost hardiness and excessive leaf loss. Although the number of frost days is currently declining in temperate Europe, events of frost may still create damage in the future in winter crops that have accumulated too much biomass in the preceding autumn.Here we report on a study in which the responses of four cultivars of winter oilseed rape (OSR) to elevated autumn temperatures and subacute levels of ammonia (NH3) were compared. It has been suggested that high concentrations of the gas, e.g. in livestock intensive regions may both act as an airborne fertiliser and reduce the frost hardiness of plants. Advancing treatments were imposed for 88 days in the autumn and consisted of pot grown plants kept in greenhouses without (ELVT) and with elevated concentrations of ammonia (ELVT+A; 195 Ī¼g m-3 NH3). Reference plants (AMB) were raised outdoors, where temperatures were 1.4Ā°C lower than in the greenhouses.After the treatments plants were all overwintered outside to study whether the pre-winter growth advancement was still discernible in the following spring. Shed leaves were collected weekly to follow how much shoot biomass was lost during and after the winter. Cultivars responded differently to warming and exposure to ammonia. Up to the winter shoot biomass was strongly increased by the advancing treatments. However, fi nal shoot mass in the following summer did not differ between cultivars and was unaffected by the higher temperatures in the preceding autumn. Nevertheless, significantly more biomass was observed in ammonia fumigated plants. Higher autumn temperatures increased leaf shedding and advanced fl owering and senescence in the next spring so that plants showed a signifi cantly reduced seed mass, harvest index and oil yield at the fi nal harvest. Obviously, the growth advancement in the preceding autumn by elevated temperatures negatively affected the availability of resources in the following spring. In contrast, plants that were grown at both elevated ammonia and temperature in the autumn showed a delayed fl owering, higher shoot and seed mass, increased harvest index and oil yield. We conclude that growth advancement by elevated autumn temperatures without the re-supply of nutrients increases leaf shedding during winter. Nevertheless, the loss of resources in winter for re-growth in spring will certainly be of minor importance for yield formation as compared to the frost damage resulting from late spring frosts
On the consistencies between CSR plant strategies and Ellenberg ecological indicator values
One strand of British comparative plant ecology has used experimental measurements of innate traits under standardized conditions to confirm plant āstrategiesā or āfunctional typesā. The Sheffield (Grime) school has now established CSR-signatures for 1010 species. In contrast, a Central-European approach (Gƶttingen or Ellenberg school) has emphasized the unity of plants with their natural habitats by allocating āecological indicator valuesā (EIVĀ“s; German: Zeigerwerte) for over 2700 species, which describe the ecological behavior of each species in their plant associations. In this paper we assess the levels of compatibility and congruence between these two approaches using large datasets that include some previously unexamined traits. Despite there being a wide gap between these plant- and environment-based starting points, we discover that both approaches lead to similar conclusions regarding patterns of evolutionary tradeoffs and ecological processes. In particular, the comparisons support the major evolutionary generalization that plant life has, in effect, aligned itself along a continuum between one trait-group that confers rapid acquisition of resources and another that confers long-term resource conservation
P-Type Silicon Strip Sensors for the new CMS Tracker at HL-LHC
The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at the CMS experiment. Based on these results, the collaboration has chosen to use n-in-p type silicon sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated this decision
Atmospheric ammonia and particulate ammonium from agricultural sources in the North China Plain
Accumulation of Aluminium and Physiological Status of Tree Foliage in the Vicinity of a Large Aluminium Smelter
A pollution gradient was observed in tree foliage sampled in the vicinity of a large aluminium production facility in Patagonia (Argentina). Leaves of Eucalyptus rostrata, and Populus hybridus and different needle ages of Pinus spec. were collected and concentrations of aluminium (Al) and sulphur (S) as well as physiological parameters (chlorophyll and lipid oxidation products) were analyzed. Al and S concentrations indicate a steep pollution gradient in the study showing a relationship with the physiological parameters in particular membrane lipid oxidation products. The present study confirms that aluminium smelting results in high Al and sulphur deposition in the study area, and therefore further studies should be carried out taking into account potentially adverse effects of these compounds on human and ecosystem health
Does elevated atmospheric CO2 allow for sufficient wheat grain quality in the future?
To identify future impacts on biomass production and yield quality of important C3 crops, spring wheat was grown in association with 13 weed species in a Mini-FACE (free-air carbon dioxide (CO2) enrichment) system under ambient (375 Ī¼l l-1) and elevated (526 Ī¼l l-1) CO2 concentrations. Wheat productivity was assessed at maturity and grain yield was subjected to various chemical analyses and baking quality tests.CO2 enrichment acted as carbon āfertiliserā and increased the aboveground biomass production of wheat by 18.8% as there was a trend towards higher stem biomass. Although not statistically significant, wheat grain yield was increased by 13.4% due to a significant establishment of more grains per unit ground area. At the same time, thousand grain weight was non-significantly shifted towards smaller grain size classes, which may result in negative consequences for the crop market value. As a result of the CO2- induced physiological and biochemical modifications, concentration of total grain protein was significantly decreased by 3.5%, reducing the wheat grain quality with potentially far-reaching impacts on the nutritional value and use for processing industry. Although often not significant, the concentrations of amino acids per unit of flour were decreased by 0.2 to 8.3% due to elevated CO2 thereby affecting the composition of proteinogenic amino acids.Furthermore, gluten proteins tended to decline. Within the significant decreased gliadins, Ī±- and Ļ5-gliadins were significantly reduced under CO2 enrichment; there was also a negative trend for Ļ1,2- and Ī³-gliadins. Changes in certain essential minerals were found as well, although not statistically significant. Concentrations of sodium, calcium, phosphorus and sulphur were slightly lowered and those of potassium and magnesium were slightly increased due to CO2 enrichment. The micro-element molybdenum was increased, while concentrations of iron, zinc, copper, manganese and aluminium were decreased. With regard to rheological and baking parameters defining the cereal quality for industrial processing, the resistance of the dough was significantly reduced by about 30%, while the extensibility was non-significantly increased by 17.1% under CO2 enrichment. Moreover, the bread volume was decreased non-significantly by about 9%. Elevated CO2 is obviously affecting grain characteristics important for consumer nutrition and health, industrial processing and marketing. Experimental evidence for these changes is still poor but deserves further attention
Effects on nutrients and on grain quality in spring wheat crops grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment 'ESPACE-wheat'
Event generator tunes obtained from underlying event and multiparton scattering measurements
New sets of parameters (ātunesā) for the underlying-event (UE) modelling of the PYTHIA8, PYTHIA6 and HERWIG++ MonteCarlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE protonāproton (pp) data at ās = 7 TeV and to UE protonāantiproton (pp) data from the CDF experiment at lower ās, are used to study the UE models and constrain their parameters, providing thereby improved predictions for protonāproton collisions at 13 TeV. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons are presented of the UE tunes to āminimum biasā (MB) events, multijet, and Drellā Yan (qq ā Z/Ī³*ālepton-antilepton+jets) observables at 7 and 8 TeV, as well as predictions for MB and UE observables at 13 TeV
Immune checkpoint inhibitor-induced neurotoxicity is not associated with seroprevalence of neurotropic infections
Measurement of the differential cross section and charge asymmetry for inclusive pp ā W\u3csup\u3eĀ±\u3c/sup\u3e + \u3ci\u3eX\u3c/i\u3e production at ā\u3ci\u3es\u3c/i\u3e = 8 TeV
The differential cross section and charge asymmetry for inclusive pp ā WĀ± + X ā Ī¼Ā±Ī½ + X production at ās = 8 TeV are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8 fbā1 recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable x from 10ā3 to 10ā1
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