1,720,968 research outputs found
Soil bulk density assessment in Europe
Full text linkThe topsoil Land Use and Cover Area frame Statistical survey (LUCAS) aims at collecting harmonised data about
the state of soil health over the extent of European Union (EU). In the LUCAS 2018 survey, bulk density has been
analysed for three depths, i.e., 0–10 cm =6140 sites; 10–20 cm =5684 sites and 20–30 cm =139 sites. The
laboratory analysis and the assessment of the results conclude that the bulk density at 10–20 cm is 5–10% higher
compared to 0–10 cm for all land uses except woodlands (20%). In the 0–20 cm depth, croplands have 1.5 times
higher bulk density (mean: 1.26 g cm3) compared to woodlands (mean: 0.83 g cm3). The main driver for bulk
density variation is the land use which implies that many existing pedotransfer rules have to be developed based
on land use. This study applied a methodological framework using an advanced Cubist rule-based regression
model to optimize the spatial prediction of bulk density in Europe. We spatialised the circa 6000 LUCAS samples
and developed the high-resolution map (100 m) of bulk density for the 0–20 cm depth and the maps at 0–10 and
10–20 cm depth. The modelling results showed a very good prediction (R2: 0.66) of bulk density for the 0–20 cm
depth which outperforms previous assessments. The bulk density maps can be used to estimate packing density
which is a proxy to estimate soil compaction. Therefore, this work contributes to monitoring soil health and
refine estimates on carbon and nutrients stocks in the EU topsoil
Soil Biodiversity Assessment across Europe
No full textSoil biodiversity is fundamental to terrestrial ecosystem functions, and its preservation is crucial for sustaining life on Earth. A wide range of studies have shown that aboveground biodiversity loss accelerates rapidly due to environmental change and intensified human activities. However, the state of soil biodiversity remains insufficiently understood and it is still unclear how different factors impact soil biota. To set effective conservation targets and preserve soil biodiversity, it is essential to deepen our understanding of how soil organisms and their functional groups (e.g., symbionts) respond to disturbances.
This PhD thesis assesses soil biodiversity across Europe using the Land Use/Cover Area Frame Survey Soil (LUCAS Soil), a soil monitoring program from the European Union. This PhD is part of a collaboration between the University of Zurich and the European Commission’s Joint Research Centre (EC-JRC) and aims to (i) understand the factors (vegetation, land-use, soil properties, and climate) driving patterns in soil biodiversity, especially for bacteria and fungi (Chapter 1), (ii) specifically examine climate impacts on key drivers of these belowground biodiversity patterns (Chapter 2), (iii) explore the effects of anthropogenic activities like pesticide use on soil biodiversity (Chapter 3), and (iv) produce the first maps of soil microbial diversity in Europe (Chapter 4).
First, this thesis highlights the high biological diversity that can be found in soils. Over 79,000 bacterial and 25,000 fungal operational taxonomic units (OTUs) were detected in 715 sites across 24 European countries. Environmental properties had a significant impact on soil microbial diversity, as we found bacterial communities to be primarily shaped by changes in soil properties, while fungi were more influenced by vegetation cover (Chapter 1). We further found that climatic conditions interacted with other key factors (e.g., land cover, pH) to shape soil microbial diversity (Chapter 2), such that spatial patterns of soil microbes were best explained when considering interactions among multiple environmental determinants.
Second, anthropogenic activities, particularly land-use intensification and pesticide use, significantly impacted soil biodiversity (Chapters 1 and 3). We found the lowest bacterial and fungal diversity in less-disturbed environments, like woodlands, compared to grasslands and highly-disturbed environments, such as croplands. Managed areas harbored distinct microbial biodiversity pools compared to less disturbed sites. Specifically, croplands contained significantly more bacterial chemoheterotrophs, a higher proportion of fungal plant pathogens and saprotrophs, and fewer beneficial fungal plant symbionts such as mycorrhizal fungi compared to woodlands and extensively-managed grasslands. Consequently, the increased taxonomic richness found in highly perturbed soils was coupled with a higher prevalence of potentially undesirable taxa (e.g., fungal plant pathogens), challenging the assumption that increased biodiversity always translates to beneficial outcomes for ecosystem functioning (Chapter 1). Importantly, we found that pesticides were major drivers of soil biodiversity patterns in Europe. Statistical models demonstrated that the impact of pesticides on belowground biodiversity was as strongly as soil characteristics and climate, not only in croplands but also in grassland and woodland areas. This is the first large-scale demonstration indicating that pesticides are such a major driver of soil biodiversity, similar to earlier observations made for bees, some insects, and birds. We observed that pesticides affected various soil organisms and functional groups differently, e.g., a higher presence of pesticides was positively associated with bacterial diversity while it negatively related to fungi. In addition, we found several non-target effects of pesticides and a complex interplay with the environmental background that warrant further investigations. (Chapter 3).
Next, we developed maps of soil microbial diversity at continental scale in Europe (Chapter 4). This was the first assessment of predicted soil biodiversity across Europe at high resolution (100 meters), identifying key drivers of soil taxa at that scale, such as soil properties, climate, vegetation, and geography.
Overall, these findings carry significant scientific and policy implications for soil biodiversity conservation. Among these, we advocate for systematic DNA-based assessments to accurately monitor soil community diversity and composition, alongside evaluating the functional profiles of detected organisms across various ecosystems, to capture a comprehensive picture of underground biodiversity (Chapters 1 and 3). Furthermore, we explore avenues for defining priority areas and developing ad-hoc conservation actions for soil biodiversity (Chapters 1, 2, and 4). This thesis also highlights that pesticides are a major factor influencing belowground biological communities. Consequently, potential improvements in pesticide risk assessment are proposed, including assessing a broader range of soil organisms and functional groups in various soil types, ecosystems – not limited to croplands, and climatic conditions (Chapter 3). In addition, we propose indicator taxa to be monitored to assess the impacts of land-use intensification and pesticide inputs on soil biodiversity (Chapters 3 and 4).
Finally, we discuss how defining concrete spatial and temporal targets for soil life monitoring and conservation at the European Union scale remains challenging due to the varied responses of soil organisms and functional groups to environmental changes. Addressing these complexities requires tackling numerous unresolved questions and fostering collaboration among scientists, policymakers, and other stakeholders. Crucially, long-term studies are key to understanding the fate of soil biodiversity, making its preservation not just an ecological concern but a global mission essential for sustaining life. Overall, this thesis demonstrates that European soils harbour highly diverse communities and it shows that the environment, land use and pesticide use have a big impact on soil organisms
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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