1,721,004 research outputs found
Particulate and mineral-associated organic matter in cropland soils: Meta-analysis of management effects
No full texthttp://dx.doi.org/10.13039/501100012166 National Key Research and Development Program of Chinahttp://dx.doi.org/10.13039/501100002365 China Agricultural Universityhttp://dx.doi.org/10.13039/501100001809 National Natural Science Foundation of Chinahttp://dx.doi.org/10.13039/501100014893 Shandong Academy of Agricultural Science
Author Correction: Soil organic carbon thresholds control fertilizer effects on carbon accrual in croplands worldwide
No full textMaize root exudate composition alters rhizosphere bacterial community to control hotspots of hydrolase activity in response to nitrogen supply
No full textImproving nitrogen (N) acquisition by crops from soil is essential to reduce fertilization rates whilst maintaining yields. Plants can adapt their nutrient acquisition strategies according to N availability, which also affects soil microbial community structure, functions and activities and relies on the supply of carbon (C) for energy. We hypothesized that N deprivation would create hotspots of N- and C-acquiring hydrolase activities in maize rhizosphere through the effects of altered root exudation on the rhizosphere bacterial community. We grew maize under three N fertilization rates and combined soil zymography with the identification of rhizosphere microbial communities and non-targeted metabolic profiling of root exudates to explore enzyme hotspot formation. The rhizosphere extents of β-1,4-glucosidase (BG) and β-N-acetylglucosaminidase (NAG) activities decreased after N fertilization, narrowing by 48% and 39%, respectively, under typical field N application rates compared to zero application. Rhizosphere extents of enzyme activities were more sensitive to altered N supply than changes in the rates of enzyme activities: BG activity decreased by ∼10%, while NAG activity was unaffected. Decreases in the activities of both hydrolases and their rhizosphere extents caused by N addition correlated with reduced abundances of oligotrophs. The relative abundances of oligotrophic bacteria (e.g., Acidobacteria) decreased, while copiotrophs (e.g., Pseudomonadota and Patescibacteria) increased under the highest N application rate. Co-occurrence networks of the rhizosphere bacterial community revealed that functional units increased with BG activity, while an efficient and denser co-occurrence network supported expansion of its rhizosphere extent. The metabolic profiles of root exudates changed according to the N application rate, suggesting that their chemistry was regulated by the plant in response to N supply. The composition of root exudates and dissolved organic C and nitrate contents explained the largest variations in NAG hotspots in the rhizosphere. In summary, maize actively adjusts the composition of root exudates to increase interactions with rhizosphere bacteria, thereby stimulating hydrolase production and activities, and altering their rhizosphere extents to mobilize N and energy (C) in a larger soil volume, under conditions of N deficiency.</p
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
Cell-autonomous targeting of arabinogalactan by host immune factors inhibits mycobacterial growth
No full textDeeper understanding of the crosstalk between host cells and Mycobacterium tuberculosis (Mtb) provides crucial guidelines for the rational design of novel intervention strategies against tuberculosis (TB). Mycobacteria possess a unique complex cell wall with arabinogalactan (AG) as a critical component. AG has been identified as a virulence factor of Mtb which is recognized by host galectin-9. Here, we demonstrate that galectin-9 directly inhibited mycobacterial growth through AG-binding property of carbohydrate-recognition domain 2. Furthermore, IgG antibodies with AG specificity were detected in the serum of TB patients. Based on the interaction between galectin-9 and AG, we developed a monoclonal antibody (mAb) screening assay and identified AG-specific mAbs which profoundly inhibit Mtb growth. Mechanistically, proteomic profiling and morphological characterizations revealed that AG-specific mAbs regulate AG biosynthesis, thereby inducing cell wall swelling. Thus, direct AG-binding by galectin-9 or antibodies contributes to protection against TB. Our findings pave the way for the rational design of novel immunotherapeutic strategies for TB control.National Key Research and Development Program of ChinaNational Key Research and Development Program of ChinaNational Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809National Natural Science Foundation of China http://dx.doi.org/10.13039/501100001809Science and Technology Commission of Shanghai Municipality http://dx.doi.org/10.13039/501100003399Science and Technology Commission of Shanghai Municipality http://dx.doi.org/10.13039/501100003399Science and Technology Commission of Shanghai Municipality http://dx.doi.org/10.13039/501100003399Tongji University http://dx.doi.org/10.13039/501100004204Excellent Young Scientists Fund http://dx.doi.org/10.13039/501100010909Shanghai Shuguang Program http://dx.doi.org/10.13039/50110001855
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