113 research outputs found

    Produtividade primária líquida do ambiente natural - indicador de sustentabilidade de sistemas de produção agrícola.

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    bitstream/CNPT-2010/40718/1/p-do100.pd

    Zoneamento agroclimático de canola para o Rio Grande do Sul.

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    bitstream/CNPT-2010/40617/1/p-co252.pd

    Growth and yield of mixed versus pure stands of Scots pine (Pinus sylvestris L. ) and European beech (Fagus sylvatica L.) analysed along a productivity gradient through Europe

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    Mixing of complementary tree species may increase stand productivity, mitigate the effects of drought and other risks, and pave the way to forest production systems which may be more resource-use efficient and stable in the face of climate change. However, systematic empirical studies on mixing effects are still missing for many commercially important and widespread species combinations. Here we studied the growth of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in mixed versus pure stands on 32 triplets located along a productivity gradient through Europe, reaching from Sweden to Bulgaria and from Spain to the Ukraine. Stand inventory and taking increment cores on the mainly 60-80 year-old trees and 0.02-1.55 ha sized, fully stocked plots provided insight how species mixing modifies the structure, dynamics and productivity compared with neighbouring pure stands. In mixture standing volume (+12 %), stand density (+20 %), basal area growth (+12 %), and stand volume growth (+8 %) were higher than the weighted mean of the neighbouring pure stands. Scots pine and European beech contributed rather equally to the overyielding and overdensity. In mixed stands mean diameter (+20 %) and height (+6 %) of Scots pine was ahead, while both diameter and height growth of European beech were behind (−8 %). The overyielding and overdensity were independent of the site index, the stand growth and yield, and climatic variables despite the wide variation in precipitation (520-1175 mm year−1), mean annual temperature (6-10.5 °C), and the drought index by de Martonne (28-61 mm °C−1) on the sites. Therefore, this species combination is potentially useful for increasing productivity across a wide range of site and climatic conditions. Given the significant overyielding of stand basal area growth but the absence of any relationship with site index and climatic variables, we hypothesize that the overyielding and overdensity results from several different types of interactions (light-, water-, and nutrient-related) that are all important in different circumstances. We discuss the relevance of the results for ecological theory and for the ongoing silvicultural transition from pure to mixed stands and their adaptation to climate change.The networking in this study has been sup-ported by COST Action FP1206 EuMIXFOR. All contributors thanktheir national funding institutions to establish, measure, and analysedata from the triplets. The first author also thanks the BayerischenStaatsforsten (BaySF) for supporting the establishment of the plots,the Bavarian State Ministry for Nutrition, Agriculture, and Forestryfor permanent support of the project W 07 ‘‘Long-term experimentalplots for forest growth and yield research’’ (# 7831-22209-2013) andthe German Science Foundation for providing the funds for the pro-jects PR 292/12-1 ‘‘Tree and stand-level growth reactions on droughtin mixed versus pure forests of Norway spruce and European beech’’.Thanks are also due to Ulrich Kern for the graphical artwork, and totwo anonymous reviewers for their constructive criticism

    Adapting evidence-informed complex population health interventions for new contexts : a systematic review of guidance

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    Background Adapting interventions that have worked elsewhere can save resources associated with developing new interventions for each specific context. While a developing body of evidence shows benefits of adapted interventions compared with interventions transported without adaptation, there are also examples of interventions which have been extensively adapted, yet have not worked in the new context. Decisions on when, to what extent, and how to adapt interventions therefore are not straightforward, particularly when conceptualising intervention effects as contingent upon contextual interactions in complex systems. No guidance currently addresses these questions comprehensively. To inform development of an overarching guidance on adaptation of complex population health interventions, this systematic review synthesises the content of the existing guidance papers. Methods We searched for papers published between January 2000 and October 2018 in 7 bibliographic databases. We used citation tracking and contacted authors and experts to locate further papers. We double screened all the identified records. We extracted data into the following categories: descriptive information, key concepts and definitions, rationale for adaptation, aspects of adaptation, process of adaptation, evaluating and reporting adapted interventions. Data extraction was conducted independently by two reviewers, and retrieved data were synthesised thematically within pre-specified and emergent categories. Results We retrieved 6694 unique records. Thirty-eight papers were included in the review representing 35 sources of guidance. Most papers were developed in the USA in the context of implementing evidence-informed interventions among different population groups within the country, such as minority populations. We found much agreement on how the papers defined key concepts, aims, and procedures of adaptation, including involvement of key stakeholders, but also identified gaps in scope, conceptualisation, and operationalisation in several categories. Conclusions Our review found limitations that should be addressed in future guidance on adaptation. Specifically, future guidance needs to be reflective of adaptations in the context of transferring interventions across countries, including macro- (e.g. national-) level interventions, better theorise the role of intervention mechanisms and contextual interactions in the replicability of effects and accordingly conceptualise key concepts, such as fidelity to intervention functions, and finally, suggest evidence-informed strategies for adaptation re-evaluation and reporting

    Growth and yield of mixed versus pure stands of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) analysed along a productivity gradient through Europe

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    SHAPE RESONANCES IN THE VALENCE-SHELL PHOTOIONIZATION OF CYANOGEN

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    Vibrationally-resolved photoelectron angular distributions for the first four valence-shell photoionizations of cyanogen have been measured with NeI, HeI and NeII line sources. Calculated photoionization cross sections and asymmetry parameters are reported for photon energies up to 50 eV. The experimental and theoretical results indicate the presence of several shape resonances

    EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE PHOTOIONIZATION OF HYDROGEN CYANIDE

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    Experimental HeI asymmetry parameters are reported for hydrogen cyanide. The HeI results do not allow conclusions to be made on the vibronic coupling between the two lowest ionic states. Multiple-scattering calculations predict that such conclusions may be possible at higher photon energies. Calculated photoionization cross sections are presented and compared with those for acetylene

    SHAPE RESONANCES IN PHOTOIONIZATION: CORRELATION WITH STO-3G MO RESULTS

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    Shape resonances in nine linear molecules are investigated by multiple-scattering and molecular-orbital calculations. Each resonance correlates with a bound-state virtual orbital. It is shown that minimal-basis-set molecular-orbital calculations may be used to guess the number of resonances expected and to estimate their energies via regression analysis

    EXPERIMENTAL AND THEORETICAL INVESTIGATION OF THE PHOTOIONIZATION OF ACETYLENE

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    Asymmetry parameters and vibrational intensity ratios for the 2Πu ionization of acetylene have been measured with different line sources (Ar II, Ne I, He I, Ne II, He II) Calculated photoionization cross sections and angular distributions are also reported for photon energies between 12 and 50 eV. In the low-energy region, experimental and theoretical results indicate the presence of processes other than direct ionization
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