糠澤 桂 (ヌカザワ ケイ)

NUKAZAWA Kei

写真a

所属

工学教育研究部 工学科土木環境工学プログラム担当

職名

准教授

外部リンク

学位 【 表示 / 非表示

  • 博士(工学) ( 2013年3月   東北大学 )

研究分野 【 表示 / 非表示

  • 社会基盤(土木・建築・防災) / 水工学

  • 環境・農学 / 環境動態解析

 

論文 【 表示 / 非表示

  • Plant debris are hotbeds for pathogenic bacteria on recreational sandy beaches 査読あり

    Suzuki Y., Shimizu H., Kuroda T., Takada Y., Nukazawa K.

    Scientific Reports   11 ( 1 )   2021年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Scientific Reports  

    On recreational sandy beaches, there are guidelines for the management of bacterial pollution in coastal waters regarding untreated sewage, urban wastewater, and industrial wastewater. However, terrestrial plant debris on coastal beaches can be abundant especially after floods and whilst it has rarely been considered a concern, the bacterial population associated with this type of pollution from the viewpoint of public health has not been adequately assessed. In this study, microbes associated with plant debris drifting onto Kizaki Beach in Japan were monitored for 8 months throughout the rainy season, summer, typhoon season, and winter. Here we show that faecal-indicator bacteria in the plant debris and sand under the debris were significantly higher than the number of faecal bacteria in the sand after a 2015 typhoon. When we focused on specific pathogenic bacteria, Brevundimonas vesicularis and Pseudomonas alcaligenes were commonly detected only in the plant debris and sand under the debris during the survey period. The prompt removal of plant debris would therefore help create safer beaches.

    DOI: 10.1038/s41598-021-91066-w

    Scopus

  • Dengue disease dynamics are modulated by the combined influences of precipitation and landscape: A machine learning approach 査読あり

    Francisco M.E., Carvajal T.M., Ryo M., Nukazawa K., Amalin D.M., Watanabe K.

    Science of the Total Environment   792   2021年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Science of the Total Environment  

    Background: Dengue is an endemic vector-borne disease influenced by environmental factors such as landscape and climate. Previous studies separately assessed the effects of landscape and climate factors on mosquito occurrence and dengue incidence. However, both factors concurrently coexist in time and space and can interact, affecting mosquito development and dengue disease transmission. For example, eggs laid in a suitable environment can hatch after being submerged in rain water. It has been difficult for conventional statistical modeling approaches to demonstrate these combined influences due to mathematical constraints. Objectives: To investigate the combined influences of landscape and climate factors on mosquito occurrence and dengue incidence. Methods: Entomological, epidemiological, and landscape data from the rainy season (July–December) were obtained from respective government agencies in Metropolitan Manila, Philippines, from 2012 to 2014. Temperature, precipitation and vegetation data were obtained through remote sensing. A random forest algorithm was used to select the landscape and climate variables. Afterward, using the identified key variables, a model-based (MOB) recursive partitioning was implemented to test the combined influences of landscape and climate factors on ovitrap index (vector mosquito occurrence) and dengue incidence. Results: The MOB recursive partitioning for ovitrap index indicated a high sensitivity of vector mosquito occurrence on environmental conditions generated by a combination of high residential density areas with low precipitation. Moreover, the MOB recursive partitioning indicated high sensitivity of dengue incidence to the effects of precipitation in areas with high proportions of residential density and commercial areas. Conclusions: Dengue dynamics are not solely influenced by individual effects of either climate or landscape, but rather by their synergistic or combined effects. The presented findings have the potential to target vector surveillance in areas identified as suitable for mosquito occurrence under specific climatic conditions and may be relevant as part of urban planning strategies to control dengue.

    DOI: 10.1016/j.scitotenv.2021.148406

    Scopus

  • Mineralogical fingerprinting to characterize spatial distribution of coastal and riverine sediments in southern Japan 査読あり

    Nukazawa K., Itakiyo T., Ito K., Sato S., Oishi H., Suzuki Y.

    Catena   203 ( 105323 )   2021年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Catena  

    Knowledge of the provenance and transport processes of coastal sediments is central to safeguarding against coastal erosion. However, to date coastal sediments have been poorly investigated without considering complex artificial and natural attributes such as coastal structures and watershed geology of potential source rivers. In this study, mineralogical fingerprinting technique was used to track the sources of sediments along a coastline in southwest Japan with reference to sediments of outflowing rivers. The sediment samples were collected from 65 beach sites along the Miyazaki Coast and its surrounding coastal area, and five river sites nearby. To determine the size distribution and geochemical and mineralogical compositions of the sediments, grain size, X-ray fluorescence, and X-ray diffraction (XRD) analyses were performed. Subsequently, cluster analysis was used to classify mineralogically similar groups in terms of XRD peak intensity ratio. The coastal sediment clusters corresponded well to nearby riverine clusters, suggesting that the coastal sediments were primarily transported from these river watersheds, although uncertainty as contributions of oceanic flows might be involved. The concordance ascribes to the major geological classifications in the watersheds of major rivers, as well as smaller rivers flowing in the northern area (e.g., the Shimanto Supergroup and Osuzuyama Acid Rocks). In addition to the major tendency, we also observed potential effects of manmade structures on the coastal sediment prevalence; the mineralogical similarities decreased across jetties in the Hitotsuse River mouth. The vertical mineralogical distribution of the core sediment samples observed on the left and right banks of the Hitotsuse River mouth supported the general trend of uniform cluster patterns in each core sample with horizontally different clusters across the river mouth. Mineralogical analysis targeting both coastal and riverine sediments is effective for understanding the characteristics of sediment distribution, which in turn is useful for efforts devoted to protection against coastal erosion.

    DOI: 10.1016/j.catena.2021.105323

    Scopus

  • Comparison of antibiotic resistance profile of Escherichia coli between pristine and human-impacted sites in a river 査読あり

    Nishimura E., Nishiyama M., Nukazawa K., Suzuki Y.

    Antibiotics   10 ( 5 )   2021年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Antibiotics  

    Information on the actual existence of antibiotic-resistant bacteria in rivers where sewage, urban wastewater, and livestock wastewater do not load is essential to prevent the spread of antibioticresistant bacteria in water environments. This study compared the antibiotic resistance profile of Escherichia coli upstream and downstream of human habitation. The survey was conducted in the summer, winter, and spring seasons. Resistance to one or more antibiotics at upstream and downstream sites was on average 18% and 20%, respectively, and no significant difference was observed between the survey sites. The resistance rates at the upstream site (total of 98 isolated strains) to each antibiotic were cefazolin 17%, tetracycline 12%, and ampicillin 8%, in descending order. Conversely, for the downstream site (total of 89 isolated strains), the rates were ampicillin 16%, cefazolin 16%, and tetracycline 1% in descending order. The resistance rate of tetracycline in the downstream site was significantly lower than that of the upstream site. Furthermore, phylogenetic analysis revealed that many strains showed different resistance profiles even in the same cluster of the Pulsed-Field Gel Electrophoresis (PFGE) pattern. Moreover, the resistance profiles differed in the same cluster of the upstream and the downstream sites. In flowing from the upstream to the downstream site, it is plausible that E. coli transmitted or lacked the antibiotic resistance gene.

    DOI: 10.3390/antibiotics10050575

    Scopus

  • Gradients of flow regulation shape community structures of stream fishes and insects within a catchment subject to typhoon events 査読あり

    Nukazawa K., Shirasaka K., Kajiwara S., Saito T., Irie M., Suzuki Y.

    Science of the Total Environment   748   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Science of the Total Environment  

    Alterations in natural flow regimes caused by dams can significantly alter the aquatic habitats of stream organisms. However, few studies have characterized flow regulation to assess its impacts on stream fauna in the context of interannually variable extreme floods. This study aims to understand the variation in stream animals along flow regulation gradients due to hydropower dams in a catchment experiencing typhoons. We observed freshwater fishes and stream insects at fully regulated sites (receiving residual flow), moderately regulated sites (receiving hydropower outflow), and nonregulated site (tributary) in the Mimi River catchment in southern Japan, in summer and winter from 2010 to 2018. We computed indicators of hydrologic alteration (IHA) in each calendar/water (July to June) year from 2007 to 2017 and selected subsets of IHA based on principal component analysis (PCA) and variance inflation factor. The largest variance was mainly explained by minimum discharge levels (e.g., 30-day annual minimum) and flow variability among IHAs, distinguishing the moderately regulated and nonregulated sites from fully regulated sites because of residual flow and suppressed high pulses in the fully regulated sites. Generalized additive models revealed that annual maxima of specific discharge were most significant predictors of fish and insect metrics while its effects were generally inconsistent between summer and winter. Non-metric multidimensional scaling revealed that insect communities were clustered into the regulation extents in both seasons. The differences in winter fauna between the regulated and nonregulated sites, characterized by Ephemeroptera-Plecoptera-Trichoptera abundance, were associated with maximum discharge and high pulse numbers. Fish community variation did not correspond to flow regime gradients. Our findings on mechanistic ecohydrological consequences of various flow regulations, supported by long-term observations, will be useful for river managers attempting to compensate for alterations in flow regime and ecological integrity.

    DOI: 10.1016/j.scitotenv.2020.141398

    Scopus

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書籍等出版物 【 表示 / 非表示

  • 河川工学

    風間 聡, 小森 大輔, 峠 嘉哉, 糠澤 桂, 横尾 善之, 渡辺 一也( 担当: 分担執筆)

    理工図書  2020年9月 

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    記述言語:日本語 著書種別:教科書・概説・概論

    CiNii Books

MISC 【 表示 / 非表示

  • ダム堆砂対策による河川生態系の応答に関する事例紹介 招待あり

    糠澤桂,鈴木祥広

    電力土木   2020年1月

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    記述言語:日本語   掲載種別:記事・総説・解説・論説等(学術雑誌)  

講演・口頭発表等 【 表示 / 非表示

  • ダムの影響を考慮した機械学習による底生動物分布モデルの構築

    田中凌央,糠澤桂,鈴木祥広

    2020年度日本水環境学会九州沖縄支部研究発表会(webリアルタイム)  (オンライン)  日本水環境学会

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    開催年月日: 2021年3月16日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:オンライン  

  • コロイド吸着と泡沫濃縮を利用した細胞外DNAの超高感度検出・定量法の開発

    玉井荘一郎,鈴木祥広,糠澤桂

    2020年度日本水環境学会九州沖縄支部研究発表会(webリアルタイム)  (オンライン)  日本水環境学会

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    開催年月日: 2021年3月16日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:オンライン  

  • 下水処理水中に生残する薬剤耐性大腸菌群から河川由来の感受性大腸菌への薬剤耐性の伝播

    謝暉,小椋義俊,糠澤桂,鈴木祥広

    第55回日本水環境学会年会(オンライン)  (オンライン)  日本水環境学会

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    開催年月日: 2021年3月10日 - 2021年3月12日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:オンライン  

  • マイクロサンドを用いたバラスト凝集処理における最適条件に関する基礎的研究

    角領将,仲元寺宣明,糠澤桂,鈴木祥広

    第55回日本水環境学会年会(オンライン)  (オンライン)  日本水環境学会

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    開催年月日: 2021年3月10日 - 2021年3月12日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:オンライン  

  • Contrasting adaptive genetic consequences of stream insects under changing climate 国際会議

    Nukazawa K., Chiu M-C., Kazama S., Watanabe K.

    The 5th International Conference on Climate Change 2021  (オンライン)  The International Institute of Knowledge Management

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    開催年月日: 2021年2月18日 - 2021年2月19日

    記述言語:英語   会議種別:口頭発表(一般)  

    開催地:オンライン  

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受賞 【 表示 / 非表示

  • 第55回環境工学研究フォーラム 優秀ポスター発表賞

    2018年12月   土木学会  

    西村恵美,糠澤桂,鈴木祥広

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

  • 応用生態工学会第22回研究発表会 優秀ポスター研究発表賞

    2018年9月   応用生態工学会  

    糠澤桂

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

  • 平成28年度建設工学研究奨励賞

    2017年6月   一般財団法人建設工学研究振興会   宮崎における分布型汚濁流出モデルの開発とその利用による河川環境・生物多様性評価

    糠澤桂

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    受賞区分:国内外の国際的学術賞  受賞国:日本国

  • 第21回地球環境シンポジウム 優秀講演賞

    2014年9月   土木学会地球環境委員会  

    糠澤桂, 風間聡, 渡辺幸三

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

  • 平成24年度東北大学 工学研究科長賞

    2013年3月   東北大学  

    糠澤桂

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    受賞国:日本国

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科研費(文科省・学振)獲得実績 【 表示 / 非表示

  • 人口減少下での中小河川の水文・環境変化と新しい管理手法の研究

    2020年04月 - 2024年03月

    科学研究費補助金  基盤研究(A)

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    担当区分:研究分担者 

  • 蚊共生細菌ボルバキアによるデング熱の生態学的制御:安心・安価な新技術の提案

    2019年10月 - 2022年03月

    科学研究費補助金  国際共同研究加速基金(国際共同研究強化(B))

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    担当区分:研究分担者 

  • 流出解析に基づく流域一貫の河川生息場モデルの高度化: 流況と空間解像度に着目して

    2019年04月 - 2022年03月

    科学研究費補助金 

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    担当区分:研究代表者 

  • インドネシア・バンドンのデング熱蚊の生態疫学:ウイルス伝播と気候変動影響の予測

    2019年04月 - 2022年03月

    科学研究費補助金  二国間交流事業共同研究

  • 健全な流砂系の回復によるサステナブル流域総合土砂管理の実証研究

    2017年04月 - 2020年03月

    科学研究費補助金  基盤研究(B)

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    担当区分:研究分担者 

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その他競争的資金獲得実績 【 表示 / 非表示

  • 泡沫濃縮・分離法を用いた高濁度水からの環境DNA検出手法の開発

    2020年04月 - 2021年03月

    民間財団等  河川基金 

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    担当区分:研究代表者  資金種別:競争的資金

  • 総合土砂管理による河川生態系への影響の定量的評価手法の開発

    2017年04月 - 2019年03月

    民間財団等  河川基金 

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    担当区分:研究分担者  資金種別:競争的資金

受託研究受入実績 【 表示 / 非表示

  • 宮崎県小丸川流域における治水と生態系の総合評価のためのモデル開発

    2018年05月 - 2021年03月

    一般受託研究 

    糠澤桂、鈴木祥広

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    担当区分:研究代表者  受託研究区分:一般受託研究

寄附金・講座・研究部門 【 表示 / 非表示

  • 工学部研究奨学寄附金

    寄附者名称:西日本技術開発(株) 2020年01月

  • 工学部の研究のため

    寄附者名称:西日本技術開発(株) 2019年01月

  • 工学部の研究のため

    寄附者名称:西日本技術開発(株) 2018年01月

  • 工学部の研究のため

    寄附者名称:西日本技術開発(株) 2017年01月

その他研究活動 【 表示 / 非表示

  • 小丸川水系生物調査

    2018年04月 - 現在