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Nitrogen cycling along a slope in Ryuoh Experimental Forest
Get PDF斜面上の異なる位置における窒素循環機構を明らかにするため, 滋賀県蒲生郡竜王山の南向き斜面に沿って, 土壌の無機態窒素の現存形態, 土壌の純窒素無機化・硝化速度と総窒素無機化・硝化速度, 土壌中の可水溶性有機炭素量, 土壌微生物バイオマス量, 土壌溶液の組成などを調査した。土壌の純窒素無機化速度は斜面に沿って一定の傾向をもたなかったが, 硝化速度は標高800mより斜面の下方で高く, 結果として土壌中の無機態窒素は斜面の下部ではおもにNO_3_--N, 上部ではNH_4_+-Nとして存在した]。土壌溶液の無機態窒素組成は, 土壌の窒素無機化特性を反映していた。線速度にみられた傾向は必ずしも純速度と整合しなかったが, 培養期間に伴う可水溶性有機炭素濃度と生成される無機態窒素の形態にみられた変化から, 総速度が経時的に変化する可能性が示唆された。土壌微生物バイオマスは斜面の上部でやや大きく, 以上の結果から斜面上の異なる位置で可給態窒素のプール, フラックスの異なる循環機構が存在することが推察された。Along a slope in Ryuoh Experimental Forest, several characteristics of nitrogen transformation in soil were measured to analyse the topographical influences on N cycling. There was no significant differences in net ammonification rates along the slope. Net nitrification rates were higher in the lower 800m of the slope than in the upper part of the slope. It resulted that inorganic N in the lower part of the slope was mainly NO3--N, while NH4+-N were main form in the upper part of the slope. Soil solution chemistry was consistent with N mineralization characteristics in soil. Gross rates were not correlated with net rates. Soluble organic C concentrations changed togather with the form of inorganic N in the lower part of the slope, it suggests that gross rate changes with time. Soil microbial biomass was larger in the upper part of the slope than in the lower part of the slope. These results suggests that there are two different N cycling mechanisms with different N pools and fluxes
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
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
Nutrient dynamics in the organic horizon of the Japanese ceder (Cryptomeria japonica)
Get PDF森林生態系の物質循環において重要な位置を占める有機物層について, そこでの物質移動量を推定するため, スギ人工林の斜面における有機物層の分布と, 有機物層における無機態窒素のプールサイズ・窒素無機化特性, および降水が有機物層を通過する際の溶存物質濃度の変化について調査した。有機物層は斜面の上部ほど厚く堆積し, 厚さの違いはおもにOe+Oa層の厚さの違いと対応していた。Oe+Oa層はOi層より無機態窒素プールが大きく, これは無機態窒素の保持機構から判断するに, Oe+Oa層がOi層より腐植含有率, 水分含有率において高いためと考えられた。窒素無機化ポテンシャルもOe+Oa層がOi層より大きい値を示した。これらの結果, Oe+Oa層の厚い斜面の上方で単位面積当たりの無機態窒素量, 窒素無機化ポテンシャルが高くなった。培養により生成される無機態窒素の形態は, 斜面の下方ほどNO_3_--Nの割合が高まった。無機態窒素の形態は無機化・不動化のエネルギー源である有機態炭素量に依存すると考えられたが, 抽出可能な有機態炭素濃度と硝化率の間に明瞭な関係はみられず, 可給態の有機態炭素の同定が必要であると考えられた。斜面上部では, 降水の有機物層の通過に伴いNH_4_+-N, Ca_, SO_4_濃度の上昇がみられ, 生育期間中の養分移動量はNで32. 2kg ha_ 5months_, Caで24. 7kg ha_ 5months_, Kで31. 2kg ha_ 5months_と推定された。NおよびKでは植物による年間の養分吸収量にほぼ等しく, 有機物層は分解および養分供給の場として機能していることが示された。一方, 斜面下部では溶存物質濃度の上昇は明らかでなく, 有機物層がリターの細分化の場となっていることが示唆された。Evaluation of the forest floor for nutrient cycling was done by studying the distribution, inorganic N pool size, characteristics of N mineralization and the amount of nutrient through the forest floor. Results showed that the forest floor accumulated thicker in the upper part of the slope than the lower part of the slope. The difference was mainly caused by Oe+Oa horizon. It had larger inorganic N pool compared to Oi horizon, because Oe+Oa horizon had higher humus and water content that affected the storage of inorganic N. Net N mineralization rate via incubation was also larger in Oe+Oa horizon than Oi horizon. Nitrate was dominated at the lower part of the slope. The organic C content seemed to controll inorganic N form, but there was no significant difference between extractable organic C content and nitrate pool size. At the ridge site, NH4-N, Ca and K concentrations in the forest floor leachate increased. The nutrient amount in the forest floor leachate for 5 months was 32.2 kg of N ha-1, 24.7 kg of Ca ha-1 and 31.2 kg of Kha-1. It was enough for annual plant uptake. ln the bottom site, no distinct increase in nutrients concentrations was noted
The influences of deer overbrowsing on nutrient cycling in forest ecosystems : Preliminary study of streamwater chemistry
No full text特集 : ニホンジカの森林生態系へのインパクト: 芦生研究林シカによる森林下層植生の喪失が森林生態系の物質循環に与える影響を明らかにするため, 京都大学芦生研究林内で防鹿柵を設置したU谷と設置しなかったK谷の各集水域末端と各集水域内の支流から5ヶ所ずつ渓流水を採取し, 水質を測定した.集水域面積が3ha未満の小集水域間では渓流水質が有意に異なったことから, 水質形成要因が空間的に不均一であることが示唆された.一方, 10ha以上の面積を持つ集水域末端では水質に差が認められず.集水域全体での水質形成機構はおおむね等しいものと考えられた.また, 柵設置後1年では渓流水質に変化が見られなかった.防鹿柵設置後の下層植生の回復は時空間的に不均一かつ漸次的であることが推測され, 集水域末端だけでなく水質形成要因の空間的不均一性を考慮できる小集水域も対象とした観測が望まれる.本調査地において小集水域を含んだ継続調査を行うことにより.シカの食害が生態系機能全体に及ぼす影響を解明できることが期待される.Currently, the decrease of forest understorey by Japanese deer overbrowsing is widely reported in Japan. In order to clarify the influences of the understorey disturbances by deer on nutrient cycling in forest ecosystem, we examined streamwater chemistry in the U watershed, where deer exclusion fence was installed over all, and in the unfenced K watershed. One outlet and four sub-catchments within each watershed were used. The wide variability of streamwater chemistry was observed among sub-catchments of both watersheds, while no significant difference was detected between both outlets. This indicates that by using not only outlets, but also the small sub-catchments within the watersheds in our study sites, we can evaluate the spatial heterogeneity of streamwater chemistry, so the effects of spatio-temporally heterogeneous and gradual recovery of understorey vegetations after deer exclusion can be expectedly comprehended in more details. The results also indicate that throughout one year since the fence installation, there has been no effect of deer exclusion on streamwater chemistry yet. Continuous observation is needed to clarify the effects of deer overbrowsing on forest ecosystem functioning and the definite impacts of atmospheric depositions to nutrient cycling in our study sites, where the watershed design is convenient for clearly demonstrating them
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
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