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61.
Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be hidden in a web of warm-hot intergalactic medium. This matter was shock-heated during the collapse of density perturbations that led to the formation of the relaxed structures that we see today. Finding the missing baryons and thereby producing a complete inventory of possibly the only detectable component of the energy-mass budget of the universe is crucial to validate or invalidate our standard cosmological model. 相似文献
62.
Ammonites are prominent in macroevolutionary studies because of their abundance and diversity in the fossil record, but their paleobiology and position in the marine food web are not well understood due to the lack of preserved soft tissue. We present three-dimensional reconstructions of the buccal apparatus in the Mesozoic ammonite Baculites with the use of synchrotron x-ray microtomography. Buccal mass morphology, combined with the coexistence of food remains found in the buccal mass, suggests that these ammonites fed on plankton. This diet may have extended to all aptychophoran ammonites, which share the same buccal mass morphology. Understanding the role of these ammonites in the Mesozoic food web provides insights into their radiation in the Early Jurassic, as well as their extinction at the end of the Cretaceous/early Paleogene. 相似文献
63.
Fabrizio Costa Sara Stella W. Eric Van de Weg Walter Guerra Michela Cecchinel Joseph Dallavia Bernie Koller Silviero Sansavini 《Euphytica》2005,141(1-2):181-190
Shelf life determines the economic life time of mature apples, which can be either freshly harvested or stored. Good shelf life is highly associated with a slow decrease of fruit firmness at room temperature. Apple is a climacteric fruit, in which loss of firmness seems to be physiologically related to ethylene. Ethylenes biosynthetic pathway is controlled by two large gene families coding for 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO).In this study, one ACS and one ACO gene were examined for their effect on ethylene production and shelf life in apple using gene specific molecular marker, and have also been positioned on a molecular marker linkage map. The ACO marker was developed in this research and mapped on linkage group (LG) 10 of the crosses Prima × Fiesta and Fuji × Mondial Gala, within the 5% border of a previously identified fruit firmness QTL [Theor Appl Genet 100 (2000) 1074]. We denoted this locus as
Md-ACO1. In addition, we mapped the previously developed Md-ACS1 marker [Theor Appl Genet 101 (2000) 742] on LG15.Studies on the cross Fuji × Braeburn revealed that Md-ACS1 and Md-ACO1 independently affect the internal ethylene concentration (IEC) as well as shelf life of apple, Md-ACS1 having the strongest effect. Descendants homozygous for Md-ACS1-2 and Md-ACO1-1 showed to have the lowest ethylene production as well as superior shelf-life. These two genes are candidates to be included in marker assisted breeding. 相似文献
64.
A procedure aimed at identifying cropping systems suitable for environmentally sensitive areas has been developed within the framework of a coordinated Italian project. It has been implemented as a DSS software named Multi-criteria Evaluation of Alternative CRopping Systems (MEACROS
which makes it possible for decision-makers to compare different scenarios based on alternative cropping systems. A set of default technical—agronomic, economic, and environmental criteria have been included in MEACROS to allow for the different impacts induced by each scenario. Users can select between the proposed set of criteria and/or in-putting new ones. The software performs concordance analysis, providing preference rankings for the alternatives, based on computed indices and allowing a good sensitivity analysis of weighted values as well as displaying the results in graphic form. Indicative results are presented here in a case study concerning a farm in a flat, sensitive area in Northern Italy. 相似文献
65.
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67.
Angioni A Dedola F Garau VL Schirra M Caboni P 《Journal of agricultural and food chemistry》2011,59(12):6806-6812
The behavior in field and the transfer from grapes to wine during winemaking of iprovalicarb, indoxacarb, and boscalid was studied. The residue levels found in grapes were far below the MRLs set for grapes in EU, accounting at harvest time 0.81, 0.43, and 4.23 mg/kg for iprovalicarb, indoxacarb, and boscalid, respectively. The residue levels in the samples treated with boscalid may have residual problems (due to an accumulation effect) if repeated field treatments will be performed. Winemaking experiments showed a complete transfer of all pesticide from grapes to the must, while in wine the residues were low or negligible due to the adsorbing effect of lees and pomace. The clarification experiments showed a good removal of pesticide residues from the wine media, for all pesticides. The GC-ITMS method showed good performance with adequate recoveries ranging from 75 to 115%, and good method limits of quantitation (LOQs) and of determination (LODs) far below MRLs. 相似文献
68.
Mattia Fumagalli Marco Acutis Fabrizio Mazzetto Francesco Vidotto Guido Sali Luca Bechini 《European Journal of Agronomy》2011,34(2):71-82
In Lombardy region (northern Italy) agricultural systems are mostly based on cereals and forage crops, and are normally intensively cultivated. To monitor and analyse the most important agri-environmental issue of this area (water pollution by nitrates and plant protection products, non-renewable fossil energy exploitation, weed dynamics), we conducted an integrated agronomic, environmental and economic assessment of arable and dairy farming using indicators.The structural and management data about farming and cropping systems were collected by periodic interviews over a 3-year period in seven (three arable and four dairy) representative farms.The nitrogen surplus calculated at field scale ranged from low (27 kg N ha?1) to high (339 kg N ha?1) values, depending by the amount of chemical and organic fertilisers applied. Fossil inputs ranged from 11.2 to 46.0 GJ ha?1; the highest values were due to the high use of machinery and chemical inputs. The efficiency factor in energy transformation (an indicator of the dependence of food and feed production on non-renewable energy) ranged from 5.0 to 12.2. Large variability was also observed for economic performance (gross margin; from -364 to 1078 € ha?1). The lowest values were observed where the total costs of production (fixed and variable) were elevated. The simplification of cropping systems was responsible for a high probability of weed populations development. The values of Load Index, an indicator describing the potential toxicity of plant protection products on non-target organisms, showed an elevated use of active substances due to the dominance of maize.The indicator-based assessment, founded on a relatively simple data collection procedure, described crop management by combining different aspects into few quantities and highlighted its critical environmental issues. The work represents a starting point for improving cropping system management in the study area; the same procedure could be re-applied if data about improved management scenarios were available. 相似文献
69.
In recent times there has been a growing dichotomy between preservation of single species and broader, ecosystem-based approaches to conservation. Freshwater habitats are among the most highly human-impacted ecosystems. We used a long-term data set on black kites (Milvus migrans), a threatened raptor dependent on aquatic habitats, to explore ways to reconcile single species and biodiversity-driven approaches to conservation. In the pre-Alpine lakes of northern Italy, black kite populations showed medium-low density, extremely low breeding success and widespread declines. Spatio-temporal variations showed density and breeding success to be positively related to ecosystem productivity (as estimated by phosphorus concentrations in lakes), availability of aquatic habitats and grassland, and to be negatively related to extent of farmland and fish harvest by professional fishermen. Fish species richness, used as a surrogate of biodiversity, was highest in one oligotrophic lake, but on average increased with increasing ecosystem productivity (i.e. lake eutrophication). Given expected future declines in ecosystem productivity, kite conservation will be helped by enhancing populations of alternative prey in terrestrial habitats (e.g. through incentives for grassland), and higher regulation of fish harvest. On the other hand, ecosystem management may profit from the use of black kites or other aerial piscivores as indicators of biodiversity and of diffuse ecosystem stress, such as sustainability of fishing practices. 相似文献
70.
Fabrizio Dabbene 《Computers and Electronics in Agriculture》2011,75(1):139-146
The aim of a traceability system is to collect in a rigorous way all the information related to the displacement of the different products along the supply chain. This information proves essential when facing food safety crisis, and allows efficiently managing the consequent product recall action. Although a recall action could be absolutely critical for a company, both in terms of incurred costs and of media impact, at present most companies do not posses reliable methods to precisely estimate the amount of product that would be discarded in the case of recall.The skill of limiting the quantity of recalled products to the minimum can be assumed as a measure of the performance and of the efficiency of the traceability system adopted by the company. Motivated by this consideration, this paper introduces novel criteria and methodologies for measuring and optimizing the performance of a traceability system. As opposed to previous introduced methods, which optimize indirect measures, the proposed approach takes into direct account the worst-case (or the average) quantity of product that should be recalled in the case of a crisis. Numerical examples concerning the mixing of batches in a sausage production process are reported to show the effectiveness of the proposed approach. 相似文献