1,721,315 research outputs found
(35(3):387-400)利用 N15 標識酸硫按探討不同土壤一水分一肥料管理方式對水稻氮吸收的影響
No full textUsing 15N-tagged ammonium sulfate fertilizers as tracers, the uptake of fertilizer N by rice (Oryza sativa L.) as influenecd by different soil-water- fertilizer management practices in Amazon varzea soil and Sacramento clay were studied under pot culture conditions. Depending on the practices the recovery of fertilizer N by rice at flowering stage was 60 to 67% in the Amazon varzea soil, while this was 25 to 59% in the Sacramento clay. Those practices which may increase development of aerobic conditions or diffusion of the applied N to the oxidized soil layers greatly reduced the applied N uptake in the Sacramento clay. This was not the case in the Amazon varzea soil. The ammonium-N applied in the Sacramento clay was found to be quickly nitrified under aerobic conditions while this was not so in the Amazon varzea soil. The soil organisms in the two soils immoblized nearly the same amount of fertilizer N (19 to 21%) while only the former soil showed some fertilizer N fixation (2 to 5%) by clay minerals which appeared to contribute some reduction in the recovery of the fertilizer N by rice. It was concluded that marked difference in the tagged N uptake depending on various practices or conditions between the two soils is attributed mainly to the high nitrification and partly to the N fixation by the clay minerals in the Sacramentoclay. Therefore, the practices (deep placement, continous flooding, slowly releasing N fertilizers and nitrification inhibitors) which may minimize the fertilizer N loss through minimizing development of nitrification may not be particularly needed in the Amazon varzea soils having very low nitrification.
本研究使用 N15 標識硫酸銨，以盆栽試驗探討巴西亞馬遜河下游沼澤土和美國沙加緬度粘土，在不同土壤一水分一肥料管理下，所施氮肥被水稻吸收利用情形。
試驗結果顯示，亞馬遜沼澤土與沙加緬度粘土水稻在開花期之氮肥回收率分別為 60~67%及 25~59%；後者依不同的土壤管辦而有很大差異。會導致土壤好氣狀態之發展或導致所施氮肥往氧化層擴散之各種土壤管理均沙使加緬度粘土之肥料回收率降低，而亞馬遜沼澤土則無此現象；前者土壤中所施銨態氮肥在好氣狀態下迅速硝酸化，而後者則否。所施肥料氮素被土壤微生物固定之量在兩種土壤差異不大（19~21%），只是沙加緬度粘土之粘土礦物略有固氮能力（2~5%）而已。故兩種土壤隨者土壤管理差異所致氮肥收率之差異主要係因沙加緬度土壤之硝化作用較盛，易導致脫氮損失所致。
為防止水田硝化作用，吾人常利用氮肥深肥，持續淹水，施用緩效性氮肥或硝化抑制度等處理，但在本試驗之亞馬遜沼澤土，因硝化作用進行極為緩慢，故上述各處理似非必要
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
C.H. Wang
No full textTitle from unverified data provided by the Bain News Service on the negatives or caption cards.Forms part of: George Grantham Bain Collection (Library of Congress).General information about the Bain Collection is available at http://hdl.loc.gov/loc.pnp/pp.ggbai
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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