Sensitivity to information upscaling of agro-ecological assessments: Application to soil organic carbon management     

Luca Bechini  Nicola Castoldi 《Agricultural Systems》2011,104(6):480-490

Upscaling of agro-ecological indicators applied in regional analyses is sensitive to scale issues of the input data. This study develops a methodology to quantify this sensitivity for an indicator of soil organic carbon (SOC) dynamics at the farming system level. A reference case consists of seven fully described farms in northern Italy. Both upscaling in complexity by substituting measured input with estimated input and upscaling in space by extending the methods to farms not included in the reference case are addressed. The indicator increased with 3-107% at four farms after substituting measured management input with that estimated by an expert, whereas it remained unchanged or decreased at the other three farms. Taking the modal value from a cluster of pedological input did not lead to additional uncertainty in most cases, and only slightly increased it in others. We evaluated spatial upscaling by including 733 farms divided in 18 clusters that were described with less information as compared to the reference farms. Within each cluster, we observed relevant variability of the indicator (coefficients of variation of 12-43%), as a consequence of the heterogeneity of farms comprised in each cluster. In each cluster we calculated the indicator for one virtual farm, defined by using modal values for basic farm inputs. In this case the indicator was highly correlated (R² = 0.98) with the average of the values obtained using measured basic farm inputs. We conclude that upscaling in complexity and space introduces uncertainty in the values of the indicator compared to the reference case. The extent of such differences depends on the variability of the systems under analysis and on indicator sensitivity.  相似文献   

The after-hours mutant reveals a role for Fbxl3 in determining mammalian circadian period     

Godinho SI  Maywood ES  Shaw L  Tucci V  Barnard AR  Busino L  Pagano M  Kendall R  Quwailid MM  Romero MR  O'neill J  Chesham JE  Brooker D  Lalanne Z  Hastings MH  Nolan PM 《Science (New York, N.Y.)》2007,316(5826):897-900

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Integration of TGF-beta and Ras/MAPK signaling through p53 phosphorylation     

Cordenonsi M  Montagner M  Adorno M  Zacchigna L  Martello G  Mamidi A  Soligo S  Dupont S  Piccolo S 《Science (New York, N.Y.)》2007,315(5813):840-843

During development and tissue homeostasis, cells must integrate different signals. We investigated how cell behavior is controlled by the combined activity of transforming growth factor-beta (TGF-beta) and receptor tyrosine kinase (RTK) signaling, whose integration mechanism is unknown. We find that RTK/Ras/MAPK (mitogen-activated protein kinase) activity induces p53 N-terminal phosphorylation, enabling the interaction of p53 with the TGF-beta-activated Smads. This mechanism confines mesoderm specification in Xenopus embryos and promotes TGF-beta cytostasis in human cells. These data indicate a mechanism to allow extracellular cues to specify the TGF-beta gene-expression program.  相似文献   

Signal-driven computations in speech processing     

Peña M  Bonatti LL  Nespor M  Mehler J 《Science (New York, N.Y.)》2002,298(5593):604-607

Learning a language requires both statistical computations to identify words in speech and algebraic-like computations to discover higher level (grammatical) structure. Here we show that these computations can be influenced by subtle cues in the speech signal. After a short familiarization to a continuous speech stream, adult listeners are able to segment it using powerful statistics, but they fail to extract the structural regularities included in the stream even when the familiarization is greatly extended. With the introduction of subliminal segmentation cues, however, these regularities can be rapidly captured.  相似文献   

Reclamation of Polluted Soil: Phytoremediation Potential of Crop-Related BRASSICA Species   总被引：2，自引：0，他引：2  

Marchiol  Luca  Sacco  Pasqualina  Assolari  Silvia  Zerbi  Giuseppe 《Water, air, and soil pollution》2004,158(1):345-356

Soils polluted by heavy metals can be reclaimed using a number of expensive tactics that either remove the contaminants or stabilize them within the soil. The value of metal accumulating plants for environmental remediation has recently been appreciated and promising results have been obtained. This paper reports a study on the behavior of Brassica napus, Brassica juncea, Raphanus sativus and Brassica carinata grown on a substrate contaminated by several heavy metals caused by the use of contaminated irrigation water. Data on carbon dioxide assimilation, biomass growth and the bioconcentration and translocation factor of each metal in each species were measured. The polluted substrate caused only a small variation in photosynthesis, however transpiration was more affected by the experimental substrate and in all three species of the genus Brassica the presence of metals in the substrate resulted in higher transpiration levels.Two bioconcentration factors were calculated respectively for the roots (BCF) and the shoots (BCF); the BCF was >1 for all the species for Cd, Cu, Ni and Zn without significant differences among species. All the values of BCF were lower than 0.5; among the metals, all Brassica species demonstrated a similar performance for Cd and Zn, whereas for other elements the bioconcentration factor was very low.  相似文献   

Utilization of the genetic resources of wild species to create a nontransgenic high flavonoid tomato     

Willits MG  Kramer CM  Prata RT  De Luca V  Potter BG  Steffens JC  Graser G 《Journal of agricultural and food chemistry》2005,53(4):1231-1236

Flavonoids represent a large and important group of plant natural products that are ubiquitous in the plant kingdom. Epidemiological studies have shown the health benefits of a diet high in flavonoids. However, the dietary intake of flavonoids in most western populations is limited, creating a need to find alternative food sources for these polyphenolic secondary metabolites. The domestication of many of our cultivated food crops has resulted in alterations in the biosynthetic pathways of many essential micronutrients and vitamins through inadvertent counterselection against nutritional traits in favor of agronomic ones. Flavonoids are nearly absent from fruits of cultivated tomato (Lycopersicon esculentum Mill.), a major vegetable in human diets. Previous attempts to restore the flavonoid pathway in tomato fruits have been limited to transgenic strategies, suggesting that the problem was intractable through traditional methods. Here, we describe for the first time a nontransgenic metabolic engineering approach to developing a high flavonoid tomato using a wild tomato species (Lycopersicon pennelliiv. puberulum) and demonstrate the opportunities for restoring functional pathways using the genetic resources of wild species, resulting in production of healthier foods.  相似文献   

Fatty acid pattern, oxidation product development, and antioxidant loss in muscle tissue of rainbow trout and Dicentrarchus labrax during growth     

Passi S  Ricci R  Cataudella S  Ferrante I  De Simone F  Rastrelli L 《Journal of agricultural and food chemistry》2004,52(9):2587-2592

The levels of hydrophilic, lipophilic, and enzymatic antioxidants, the oxidative damage to lipids and proteins, and the fatty acid patterns of triglyceride and phospholipid fractions were assayed in fresh muscle tissue of rainbow trouts (Oncorhynchus mykiss) and sea basses (Dicentrarchus labrax) during aging, to investigate the correlation between oxidative stress and aging processes in fish. The present studies suggests that lipid peroxidation and accumulation of oxidized proteins during in vivo aging are most likely to be linked with an age-dependent decline of lipophilic antioxidants (CoQH(2), CoQ, and vitamin E) and vitamin C contents in muscle tissue, whereas fish aging is not linked to a decline in antioxidant enzymes and reduced glutathione levels. Lipophilic antioxidant and vitamin C levels represent a reliable marker of oxidative stress during aging, and their determination might be useful for the assessment of fish age.  相似文献   

Mechanism of action of vitamin A in differentiation of mucus-secreting epithelia   总被引：2，自引：0，他引：2  

L De Luca  G Wolf 《Journal of agricultural and food chemistry》1972,20(3):474-476

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Isoflavonoids isolated from Cuban propolis   总被引：3，自引：0，他引：3  

Piccinelli AL  Campo Fernandez M  Cuesta-Rubio O  Márquez Hernández I  De Simone F  Rastrelli L 《Journal of agricultural and food chemistry》2005,53(23):9010-9016

Chemical investigation of a red-type Cuban propolis sample has led to the isolation of 11 isoflavonoids (2 isoflavones, 3 isoflavans, and 6 pterocarpans), together with gallic acid, isoliquiritigenin, and (-)-liquiritigenin. Structural determination, including the absolute stereochemistry, was accomplished by spectroscopic analysis, particularly CD and 2D NMR techniques. The fragmentation behavior of pterocarpans was studied by electrospray ionization (ESI) tandem mass spectrometry (MS/MS) using an ion-trap analyzer, and a generalized fragmentation pathway, useful in the identification and structural characterization of pterocarpans, is proposed. Isoflavonoids are reported for the first time from propolis samples.  相似文献   

Activity of spinosad on stored-tobacco insects and persistence on cured tobacco stripst     

Blanc MP  Panighini C  Gadani F  Rossi L 《Pest management science》2004,60(11):1091-1098

Every year raw tobacco and manufactured tobacco products are lost to two major storage pests, the cigarette beetle, Lasioderma serricorne (F) and the tobacco moth, Ephestia elutella (Hiibner). Post-harvest management of both insects is achieved through sanitation, insect monitoring and fumigation with phosphine. However, insect resistance to phosphine and control failures have been reported, and fumigants are under constant regulatory pressure. Here we report the evaluation of spinosad, a bioinsecticide derived from the fermentation of the soil micro-organism Saccharopolyspora spinosa Mertz & Yao. Spinosad was first registered in 1997 and is now widely used as a field pest control agent on many crops, including tobacco. The insecticidal activity of the fermentation product (technical spinosad, TS) was measured by diet incorporation assays against L serricorne and E elutella larvae. Mortality levels were determined on newly hatched larvae and over the whole insect life cycle. For both species, no emergence of adult insects was observed in cured tobacco sprayed with 50mg TS kg(-1) and inoculated with eggs or newly hatched larvae. These results indicated that spinosad has potential for the control of both species in stored tobacco, since 100% control of both pests could be achieved at 50 mg TS kg(-1), and with almost full control (90-95%) at 10 mg kg(-1). We also monitored the stability of the product on cured tobacco. The original concentration of the main active component of TS, spinosyn A, did not change significantly over 18 months, indicating no loss of spinosad during a typical leaf storage period of time. Bioassays against larvae confirmed that the bioinsecticidal activity of spinosad was retained.  相似文献