1,720,973 research outputs found
Increasing bioenergy production on arable land: Does the regional and local climate respond? Germany as a case study
Full text linkThe extent and magnitude of land cover change effect on local and regional future climate during the vegetation period due to different forms of bioenergy plants are quantified for extreme temperatures and energy fluxes. Furthermore, we vary the spatial extent of plant allocation on arable land and simulate alternative availability of transpiration water to mimic both rainfed agriculture and irrigation. We perform climate simulations down to 1 km scale for 1970-1975 C20 and 2070-2075 A1B over Germany with Consortium for Small-Scale Modeling in Climate Mode. Here an impact analysis indicates a strong local influence due to land cover changes. The regional effect is decreased by two thirds of the magnitude of the local-scale impact. The changes are largest locally for irrigated poplar with decreasing maximum temperatures by 1 degrees C in summer months and increasing specific humidity by 0.15 g kg(-1). The increased evapotranspiration may result in more precipitation. The increase of surface radiative fluxes R-net due to changes in latent and sensible heat is estimated by 5 W m(-2) locally. Moreover, increases in the surface latent heat flux cause strong local evaporative cooling in the summer months, whereas the associated regional cooling effect is pronounced by increases in cloud cover. The changes on a regional scale are marginal and not significant. Increasing bioenergy production on arable land may result in local temperature changes but not in substantial regional climate change in Germany. We show the effect of agricultural practices during climate transitions in spring and fall
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
Quantification of Biomass Production Potentials from Trees Outside Forests—A Case Study from Central Germany
No full textA review of the impacts of Short Rotation Coppice cultivation on water issues
No full textCultivation of Short Rotation Coppice (SRC) with poplars (Populus sp.) and willows (Salix sp.) for production of biomass for heat and/or electricity is energy effective and coincides with several environmental objectives. Since an increase of cultivation of poplar and willow SRC has been projected in Europe, the consequent implications on water issues arises. For instance, water use of SRC can be higher compared to annual agricultural crcps or previous set-aside land, but water quality can be improved The paper examines such implications based on a review of the existing scientific literature. Rates of evapotranspiration (V(ET)) of SRC are reported to be fairly higher than arable crops, but reported values vary markedly and are related to site-specific factors such as the local precipitation and conditions (e.g soil type, temperature, groundwater level), the species/sorts and the age of the crop, and their interactions. Despite the predicted local effects on water balances, effects on water balances/hydrology on catchment levels have not been reported or justified This, combined with the reported positive effects of SRC on groundwater quality in terms of nutrient leaching, imoly average positive effects of SRC on water issues, if the identified potentially negative impacts would be considered and minimized. For this, comparisons of V ET between SRC and arable crops, and the relation of V ET with local precipitation and other local factors (root development, groundwater availability) should be better examined and combined with positive effects of SRC on groundwater leaching compared to other crops Upscaling of water issues for SRC is needed to promote future decision-making processes with respect to the envisaged broadening of SRC on productive but also on marginal soils
A review of the impacts of Short Rotation Coppice cultivation on water issues
No full textCultivation of Short Rotation Coppice (SRC) with poplars (Populus sp.) and willows (Salix sp.) for production of biomass for heat and/or electricity is energy effective and coincides with several environmental objectives. Since an increase of cultivation of poplar and willow SRC has been projected in Europe, the consequent implications on water issues arises. For instance, water use of SRC can be higher compared to annual agricultural crcps or previous set-aside land, but water quality can be improved The paper examines such implications based on a review of the existing scientific literature. Rates of evapotranspiration (V(ET)) of SRC are reported to be fairly higher than arable crops, but reported values vary markedly and are related to site-specific factors such as the local precipitation and conditions (e.g soil type, temperature, groundwater level), the species/sorts and the age of the crop, and their interactions. Despite the predicted local effects on water balances, effects on water balances/hydrology on catchment levels have not been reported or justified This, combined with the reported positive effects of SRC on groundwater quality in terms of nutrient leaching, imoly average positive effects of SRC on water issues, if the identified potentially negative impacts would be considered and minimized. For this, comparisons of V ET between SRC and arable crops, and the relation of V ET with local precipitation and other local factors (root development, groundwater availability) should be better examined and combined with positive effects of SRC on groundwater leaching compared to other crops Upscaling of water issues for SRC is needed to promote future decision-making processes with respect to the envisaged broadening of SRC on productive but also on marginal soils
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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