Importance of Flow Metrics on Modeling Macroinvertebrate Community in Dammed Rivers: An Approach With Optimized Gradient Boosting

Habitat models that can predict the habitat suitability for riverine organisms and their distribution along environmental gradients are helpful in watershed environmental management. However, the impacts of dams on riverine communities and their habitats have not yet been considered in such models, although dams have considerably altered important riverine habitats. In this study, we aim to develop catchment-scale habitat models of macroinvertebrate communities with predictor variables characterizing the impacts of dams. We studied the Omaru River catchment in southwest Japan, where the river flow has been altered considerably because of multiple hydropower dams. Multiple machine learning techniques, such as XGBoost and LightGBM were used to model the habitat distributions of 170 macroinvertebrate taxa observed throughout the river catchment. We used predictor variables of dam impacts derived based on geographical information system data (hereafter, dam metrics) and physically simulated flow data using a hydrological model. Among the modeling techniques, gradient boosting algorithms (XGBoost and LightGBM) with optimized tree number parameters exhibited the highest mean accuracy among the analyzed taxa, followed by the random forest algorithm. The accuracy of the habitat models for the macroinvertebrate community and habitat groups considerably improved with the integration of dam metrics and flow predictors. Of the habit groups considered, clingers showed a keen response to low-flow metrics, presumably owing to flow alteration caused by the studied dams, as the downstream sections of these dams received only residual flow. Our findings indicate that (1) variables of dam impacts greatly improve the predictive capability of macroinvertebrates and (2) gradient boosting machines with optimized parameters are favorable for habitat modeling of the biotic community. Our models are helpful when river practitioners implement conservation measures as they better understand the environmental consequences of their flood pro

Year-round monitoring of antibiotic-resistant bacteria in pristine uppermost stream and estimation of pollution sources

Citation: Emi Nishimura, Hui Xie, Soichiro Tamai, Masateru Nishiyama, Kei Nukazawa, Yuki Hoshiko, Yoshitoshi Ogura, Yoshihiro Suzuki, Year-round monitoring of antibiotic-resistant bacteria in pristine uppermost stream and estimation of pollution sources, Frontiers in Environmental Science, 12, 2024-09-09, https://doi.org/10.3389/fenvs.2024.143917

分子軌道法による原子炉用ジルコニウム合金の耐食機能設計

現在の主要な発電用原子炉において、その炉心部分にはジルコニウム合金が使われている。このジルコニウム合金の表面には、局部腐食(いわゆるノジュラ-腐食)が起こり問題となっている。さらに、ウラン資源の有効利用を目的として進められている核燃料の高燃焼度化の要請とあいまって、腐食ジルコニウム合金の開発が強く望まれている。本研究はこのような背景のもとに計画されたものであり、分子軌道法による電子状態の計算とX線光電子分光(XPS)などの実験を併用して、高耐食ジルコニウム合金の設計と開発の指針を得ることを目標にしている。ジルコニウム合金の表面にできる腐食生成物であるZrO_2(ジルコニア)については、これまでいろいろな方法で調べられてきたが、XPSによる表面皮膜の解析は新しく、その化学成分や電子状態について興味ある情報を得ることができた。例えば、 XPSスペクトルは耐食性の良い合金と悪い合金とでは違っていることがわかった。合金元素の周期表の位置に従って耐食性が変わることも明らかになった。さらに、ジルコニウア皮膜自体、決して均一なものではなく、膜厚方向に合金元素の濃度勾配があることもわかった。また、DV-Xα分子軌道計算からによるジルコニウムおよびジルコニア中の合金元素の振舞いを明らかにした。そして電子論に基づくジルコニウム合金の腐食メカニズムを初めて提案した。本研究を通し、ジルコニウムの腐食を新しい視点から捉えることができた。その結果、新しい高耐食性ジルコニウム合金を開発するときに有用な指針が得られた。科学研究費補助金 研究種目:研究(A)(1) 課題番号:07555500 研究代表者:森永 正彦 研究期間:1995-1996年度research repor

Antibiotic-resistant Escherichia coli isolated from dairy cows and their surrounding environment on a livestock farm practicing prudent antimicrobial use

application/pdfOn a livestock farm where antimicrobial administration and its history had been managed for prudent use of antimicrobials, we surveyed antibiotic-resistant Escherichia coli strains isolated from cow feces and the surrounding environment （i.e., rat and crow feces, and water samples from a drainage pit and wastewater processing tank） every month for 1 year. Two strains （1.7%） in cow feces were resistant to tetracycline, whereas all other strains were susceptible to all other antimicrobials. Among 136 strains isolated from cows and wild animals, only one ampicillin-resistant strain was identified. The antibiotic resistance rate in the drainage from the barn was 8.3% （10/120）, and all strains showed susceptibility for 8 months of the year. Tetracycline resistance was common in all resistant strains isolated from animal feces and water samples; all tetracycline-resistant strains carried tetA. These results strongly support the proper use and management of antibiotics on farms to minimize the outbreak and spread of antibiotic-resistant bacteria

Observation of the ηc(2S) in Exclusive B→KKSK-π+ Decays

journal articl

ミュージアム施設と市民活動団体との連携に関する考察－神奈川県内のミュージアム、茅ヶ崎市内活動団体の実情から－

departmental bulletin pape

Modification Effect of La on the Adsorption Behavior of CH_4 on MgO

application/pdfThe modification effect of La on CH_4-adsorption was examined. In the presence of surface OH， exposure of CH_4 caused the production of RCO species on MgO， while olefinic species was mainly produced on La-doped MgO. In the case of CH_4-pretreated surface， ammonia formed NCO species on MgO， not on La-doped MgO. We conclude that the higher selectivity of C_2 compounds in oxidative coupling of methane on La-doped MgO is ascribed to La's inhibition effect on breaking olefinic C-C bond produced from CH_4 ； this breaking forms RCO species leading to CO_x species.departmental bulletin pape

eDNAメタバーデータ

genomic dat

Supplementary Tables S1 and S2

Table S1: Presence or absence of 171 macroinvertebrate taxa modeled in the study (provided as a spreadsheet). Note that the second alphabet of “site” represents Mainstream, Tributary or Dogawa and numerical value increases as it goes upstream (e.g., OM01 is the downermost site along a mainstream) Table S2: Environmental parameters used in the study (provided as a spreadsheet). Note that the second alphabet of “site” represents Mainstream, Tributary or Dogawa and numerical value increases as it goes upstream (e.g., OM01 is the downermost site along a mainstream)datase

Characterization of P-TEFb retention by HeLa cell nuclei using differential salt extraction

<p><b>Copyright information:</b></p><p>Taken from "Inhibition of HIV-1 replication by P-TEFb inhibitors DRB, seliciclib and flavopiridol correlates with release of free P-TEFb from the large, inactive form of the complex"</p><p>http://www.retrovirology.com/content/4/1/47</p><p>Retrovirology 2007;4():47-47.</p><p>Published online 11 Jul 2007</p><p>PMCID:PMC1948018.</p><p></p> Untreated HeLa cells and HeLa cells treated for 1 hour with 100 μM DRB were lysed with a buffer containing the indicated amounts of NaCl to generate cytosolic extracts (CE). The CE and the nuclear pellet (NP) were examined by immunoblotting with the indicated antibodies for the presence of P-TEFb or the TFIIH components p62, Cdk7 and cyclin H