1,720,965 research outputs found
Annual and Perennial Crops for Bioenergy: Soil and Environmental Issues
No full textPerennial and annual crops for bioenergy production are increasing. Much of
the biomass and oil used for energetic purpose come from cultivations where
bioenergy crops are grown with relatively high inputs. Large amounts of
nutrients are removed from the soil with the harvest; and inorganic fertilizers
lead to risks of soil water pollution. This chapter reviews the effect of bioenergy
crops cultivation on soil chemical, physical, and biological properties. Variation
is considerable, soil organic C decreased in most soils under conventional row
crops, also, soil N2O emissions are common as a result of the use of N fertilizers.
There is some evidence for high leaching losses of fertilizer nutrients and loss
of biodiversity. Soil erosion is a problem on newly planted land in many parts
of the world. It is concluded that annual and perennial bioenergy crops can
both substantially contribute to the supply of renewable energy, but an improved
crop management is needed to sustain and improve the resource base on which
production depends
Differenziazione a Fiore della Gemma Apicale in Carciofo: Interazione tra Temperatura ed Applicazione di Acido Gibberellico
No full textAnnual and Perennial Crops for Bioenergy: Soil and Environmental Issues
No full textPerennial and annual crops for bioenergy production are increasing. Much of
the biomass and oil used for energetic purpose come from cultivations where
bioenergy crops are grown with relatively high inputs. Large amounts of
nutrients are removed from the soil with the harvest; and inorganic fertilizers
lead to risks of soil water pollution. This chapter reviews the effect of bioenergy
crops cultivation on soil chemical, physical, and biological properties. Variation
is considerable, soil organic C decreased in most soils under conventional row
crops, also, soil N2O emissions are common as a result of the use of N fertilizers.
There is some evidence for high leaching losses of fertilizer nutrients and loss
of biodiversity. Soil erosion is a problem on newly planted land in many parts
of the world. It is concluded that annual and perennial bioenergy crops can
both substantially contribute to the supply of renewable energy, but an improved
crop management is needed to sustain and improve the resource base on which
production depends
Predicting growth and yield of winter rapeseed in a Mediterranean environment: Model adaptation at a field scale
No full textDifferenziazione a Fiore della Gemma Apicale in Carciofo: Interazione tra Temperatura ed Applicazione di Acido Gibberellico
No full textPotential Biogas Production from Artichoke Byproducts in Sardinia, Italy
No full textThe paper aims at evaluating the potential biogas production, both in terms of CH4 and theoretical energy potential, from globe artichoke agricultural byproducts in Sardinia. Field data about the productivity of byproducts were collected on five artichoke varieties cultivated in Sardinia, to assess the biomethane production of their aboveground non-food parts (excluding the head). Moreover, secondary data from previous studies and surveys at regional scale were collected to evaluate the potential biogas production of the different districts. Fresh globe artichoke residues yielded, on average, 292.2 Nm(3)t(DOM)(-1), with dissimilarities among cultivars. Fresh samples were analyzed in two series: (a) wet basis; and (b) wet basis with catalytic enzymes application. Enzymes proved to have some beneficial effects in terms of anticipated biomethane availability. At the regional level, ab. 20 x 10(6) Nm(3) CH4 could be produced, corresponding to the 60% of current installed capacity. However, districts potentials show some differences, depending on the specific biomass partitioning and on the productivity of cultivated varieties. Regional assessments should encompass the sensitiveness of results to agro-economic variables and the economic impacts of globe artichoke residue use in the current regional biogas sector
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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