检索结果-内蒙古大学图书馆

Groundwater quality, human health risks and major driving factors in arid and semi-arid regions of Rajasthan, India

JOURNAL OF CLEANER PRODUCTION 2023年 427卷

作者： Pandey, Suchitra Mohapatra, Geetilaxmi Arora, Rahul Birla Inst Technol & Sci Dept Econ & Finance Pilani Campus Pilani 333031 Rajasthan India

Evaluating status, variability and identifying the factors influencing groundwater quality is essential to manage and conserve groundwater resources. The present study aims to examine groundwater quality for 15 water quality parameters from 84 stations in arid and semi-arid districts of Rajasthan, India, using annual data from 2000 to 2018. Statistical methods such as descriptive test statistics, Mann-Kendall (MK) test, Sen's slope estimation, and Principal component analysis (PCA) were used to analyze the hydrochemical parameters. While World Health Organisation (WHO) and Bureau of Indian Standards (BIS) guidelines were used to assess the suitability of groundwater for domestic purposes, sodium adsorption ratio (SAR), electrical conductivity (EC), and United States Salinity (USSL) diagrams were used for irrigation suitability. Further generalized additive Model (GAM) was used to explore the effect of climatic (precipitation, temperature) and anthropogenic (net irrigated area (NIA), fertilizer usage, industrialization, and population) variables on groundwater quality. The empirical results reveal that in groundwater of the study area sodium (Na+) and potassium (K+) were the dominating cations, while chloride (Cl-) and bicarbonate (HCO3-) were the dominating anions. The groundwater was predominantly Na-Cl type. Further, most stations witnessed an increasing trend in calcium, magnesium, sodium, chloride, bicarbonate and sulphate and a decreasing trend in potassium, fluoride and nitrate. The SAR, EC, and USSL indicate that the groundwater in the region is suitable for irrigation if salinity control measures are implemented. Chloride, fluoride and sodium concentrations exceeded the prescribed guideline limits in most stations, jeopardizing the suitability of water for drinking and posing significant health hazards. The GAM analysis revealed that anthropogenic variables significantly impact the groundwater quality parameters compared to the climatic variables. Accordingl

关键词： Anthropogenic variables Climate change generalized additive models Groundwater quality Mann -Kendall (MK) test Arid and semi -arid regions Drinking suitability Irrigation suitability

来源：评论

学校读者我要写书评

暂无评论

Added value of a multiparametric eddy-driven jet diagnostic for understanding European air stagnation

引用

ENVIRONMENTAL RESEARCH LETTERS 2023年第8期18卷 084022-084022页

作者： Maddison, J. W. Ayarzagueena, B. Barriopedro, D. Garcia-Herrera, R. Univ Complutense Madrid Dept Earth Phys & Astrophys Madrid Spain CSIC UCM Inst Geociencias IGEO Madrid Spain

Air stagnation refers to an extended period of clear, stable conditions which can favour the accumulation of pollutants in the lower atmosphere. In Europe, weather conditions are strongly mediated by the North Atlantic eddy-driven jet stream. Descriptions of the jet stream typically focus on its latitudinal position or the strength of its wind speed, and its impacts are often studied under different latitudinal regimes of the jet. Herein, we evaluate the influence of the jet stream on European air stagnation using a new multiparametric jet diagnostic that provides a more complete description of jet stream characteristics. We report large influences of the jet stream on regional stagnation and uncover links with jet structure that go beyond knowledge of its latitude. Accordingly, air stagnation anomalies show different, and often opposite, responses to jets in a given latitudinal position but with different additional characteristics. Statistical modelling reveals that the monthly variability in air stagnation explained by the new jet diagnostic is substantially higher compared to one that only considers the jet's latitude and intensity. Knowledge of the average location of the jet in a given month, as described by a latitude or longitude parameter, together with the variability in the jet's shape, appear key for the statistical models of air stagnation. The relationship between air stagnation and the jet stream is often nonlinear, particularly for regions in southern Europe. For northern regions it is generally more linear, but the additional jet parameters are essential for describing stagnation variability. These results have implications for studying air stagnation and its pollution impacts in seasonal forecasts and climate change projections.

关键词： eddy-driven jet air stagnation multilinear regression generalized additive models

来源：评论

学校读者我要写书评

暂无评论

Early Warning Indicators of Groundwater Drought in Mountainous Regions

引用

WATER RESOURCES RESEARCH 2023年第8期59卷 e2022WR033399-e2022WR033399页

作者： Gullacher, A. Allen, D. M. Goetz, J. D. Simon Fraser Univ Dept Earth Sci Burnaby BC Canada Minist Forests River Forecast Ctr Victoria BC Canada

Aquifers in mountainous regions are susceptible to drought. However, the diverse hydroclimatology, the small and responsive aquifers, and the varied nature of interactions between groundwater and surface water lead to complex groundwater level responses that are challenging to interpret for understanding groundwater drought. In this study, generalized additive models (GAMs) are used to explore the sensitivity of summer groundwater levels to various climate and hydrological predictor variables (indicators) in each of a snowmelt- and rainfall-dominated hydroclimatic regime in British Columbia, Canada. A sensitivity analysis explores individual seasonal predictor variables, station versus gridded climate data, teleconnection indices, and time series length. GAMs are then generated for different combinations of predictor variables to identify the best combination for each region. In the snowmelt-dominated regime, maximum spring temperature, maximum snow water equivalent, and the winter Nino 3.4 index is the best combination of variables for predicting summer groundwater levels. In the rainfall-dominated regime, maximum spring temperature, winter precipitation, and spring streamflow is the best combination. The unique combinations of predictor variables for each region can be used as early warning indicators for groundwater drought preparedness by water managers prior to the beginning of the summer. The Standardized Groundwater Level Index (SGI) is also effective at indicating which wells had pronounced responses to periods of drought in each region. However, the SGI differed among aquifers of similar type, suggesting other factors such as aquifer response mechanism and groundwater pumping may have an important influence on the SGI.

关键词： groundwater drought indicators generalized additive models mountain regions prediction

来源：评论

学校读者我要写书评

暂无评论

The nocturnal distribution of deep-pelagic fish on the continental slope of the Bay of Biscay

引用

PROGRESS IN OCEANOGRAPHY 2023年第1期216卷

作者： Loutrage, Liz Spitz, Jerome Iglesias, Samuel P. Brind'Amour, Anik Rochelle Univ Observ Pelagis CNRS UAR 3462 La Rochelle France INRAE Inst Agrocampus Ecosyst Dynam & Sustainabil UMR DECOD IFREMER Nantes France Rochelle Univ Ctr Etud Biol Chize CEBC CNRS UMR 7372 Villiers En Bois France Sorbonne Univ Univ Antilles Inst Systemat Evolut Biodiversite ISYEB Stn Marine ConcarneauMuseum Natl Hist NaturelleC Concarneau France Rochelle Univ Observ Pelagis CNRS UAR 3462 5 Allees Ocean La Rochelle France

The biomass of deep-sea pelagic fishes could represent more than 90% of the total fish biomass on earth, which represents an important potential for exploitation. However, this community plays multiple key ecological roles in biogeochemical cycles and food webs. Information on their ecology and function is needed to plan effective sustainable conservation measures. In particular, the distribution of deep-sea pelagic fish biomass and the environmental factors that control it remain poorly understood on slope areas at the interface of coastal and oceanic habitats. The combined use of biological data collected by pelagic trawling between 20 and 2000 m depth at night and 16 environmental variables allowed us to study the distribution of this community on the continental slope of the Bay of Biscay, NE Atlantic. Multivariate regression tree analysis suggested that immersion depth was the most important variable structuring this community by night, defining four depth assemblages with different indicator species (i.e. organisms whose presence, absence, or biomass reflects specific environmental conditions): the epipelagic (20-175 m), the upper mesopelagic (175-700 m), the lower mesopelagic (700-1000 m) and the bathypelagic assemblage (1000-2000 m). The use of generalized additive models indicated a positive relationship between bottom proximity and biomass for three of the four assemblages. This contrasts with the paradigm in open ocean areas where the biomass of mesoand bathypelagic fishes decreases with depth. The echograms also showed low acoustic detection at the surface at night, which differs from the open ocean models where nocturnal migration results in a high density of mesopelagic organisms in the epipelagic layer. Different mechanisms could explain this relationship, such as the concentration of food resources in the benthic boundary layer, an ontogenetic change of some species, active horizontal migration, or a demersal spawning behavior. This specific distribu

关键词： Mesopelagic Bathypelagic Vertical distribution Benthic boundary layer generalized additive models Biomass

来源：评论

学校读者我要写书评

暂无评论

Robust multipe imputation with GAM

引用

STATISTICS AND COMPUTING 2024年第4期34卷 121-121页

作者： Templ, Matthias Univ Appl Sci & Arts Northwestern Switzerland Inst Competitiveness & Commun Riggenbachstr 16 CH-4600 Olten Switzerland

Multiple imputation of missing values is a key step in data analytics and a standard process in data science. Nonlinear imputation methods come into play whenever the linear relationship between a response and predictors cannot be linearized by transformations of variables, adding interactions, or using, e.g., quadratic terms. generalized additive models (GAM) and its extension, GAMLSS-where each parameter of the distribution, such as mean, variance, skewness, and kurtosis, can be represented as a function of predictors, are widely used nonlinear methods. However, non-robust methods such as standard GAM's and GAMLSS's can be swayed by outliers, leading to outlier-driven imputations. This can apply concerning both representative outliers-those true yet unusual values of your population-and non-representative outliers, which are mere measurement errors. Robust (imputation) methods effectively manage outliers and exhibit resistance to their influence, providing a more reliable approach to dealing with missing data. The innovative solution of the proposed new imputation algorithm tackles three major challenges related to robustness. (1) A robust bootstrap method is employed to handle model uncertainty during the imputation of a random sample. (2) The approach incorporates robust fitting techniques to enhance accuracy. (3) It effectively considers imputation uncertainty in a resilient manner. Furthermore, any complex model for any variable with missingness can be considered and run through the algorithm. For the real-world data sets used and the simulation study conducted, the novel algorithm imputeRobust which includes robust methods for imputation with GAM's demonstrates superior performance compared to existing imputation methods using GAMLSS. Limitations pertain to the imputation of categorical variables using robust techniques.

关键词： Missing values Multiple imputation generalized additive models Robust estimation Robust bootstrap

来源：评论

学校读者我要写书评

暂无评论

Environmental factors affecting the distribution of deep-water rose shrimp (Parapenaeus longirostris, Lucas, 1846 ) abundance in the Strait of Sicily (Mediterranean Sea)

引用

CONTINENTAL SHELF RESEARCH 2024年 282卷

作者： Bignami, Francesco Fiorentino, Fabio Garofalo, Germana Zambianchi, Enrico Colella, Simone Sorgente, Roberto Olita, Antonio Landolfi, Angela Quattrocchi, Federico Miller, Peter I. CNR ISMAR SS Roma Via Fosso Cavaliere 100 I-00133 Rome Italy CNR IRBIM SS Mazara Vallo Via L Vaccara 61 I-91026 Mazara Del Vallo TP Italy Univ Napoli Parthenope Naples Italy CoNISMa Naples Italy CNR IAS SS Oristano I-09170 Oristano OR Italy Univ Cagliari CNR ISAC Cagliari Dipartimento Fis Str Pro le MonserratoSestu Km 0 700 I-09042 Cagliari CA Italy Plymouth Marine Lab Remote Sensing Grp Prospect Pl Plymouth PL1 3DH England SZN Stn Zool Anton Dohrn SZN Lungomare Cristoforo Colombo 4521 I-90149 Palermo Italy Univ Palermo Dept Earth & Marine Sci DiSTeM I-90123 Palermo Italy Natl Biodivers Future Ctr Palermo Italy

The distribution of deep-water rose shrimp (Parapenaeus longirostris, FAO 3 alpha code DPS), the main target species of demersal fisheries in the Strait of Sicily, is investigated in relation to surface parameters and biogeochemical processes. Such processes are known to influence sea bottom habitats and may be particularly relevant to the Strait of Sicily because of its relative shallowness and high surface primary production. Shrimp abundances recorded during multi-annual and seasonal trawl surveys (2004-2008) are analyzed. A GAMM and GAM model analysis is performed comparing juvenile abundances to monthly mean spatial patterns of remotely-sensed sea surface temperature (SST) and surface chlorophyll (chl), as well as their frontal structures, with a time-lag of one month, given the pelagic behavior of DPS early life stages preceding settlement. Juvenile and total shrimp abundances are also compared to the flux of particulate organic carbon (POC) to the seabed. The POC flux is computed via 1-D and 3-D models simulating sinking, re-mineralization and horizontal advection and diffusion of surface POC. The latter is derived from surface primary production maps obtained from ocean color data. Results show that the abundance of the juvenile fraction of DPS is significantly correlated with depth, distance to SST fronts and the intensity of chl fronts (correlation R-2 = 80%). Furthermore, results strongly suggest the significant role of bottom POC flux in conditioning the distribution of DPS abundance, indicating that ecological processes occurring in surface waters influence food availability near the seabed in the investigated area.

关键词： Deep-water rose shrimp SST Chlorophyll Fronts POC generalized additive models

来源：评论

学校读者我要写书评

暂无评论

Variability in estuarine habitat use of a threatened species in the northern Gulf of Mexico: implications for coastal restoration

引用

GLOBAL ECOLOGY AND CONSERVATION 2024年 49卷

作者： Brogdon, Jenna N. Baer, Ashley Constant, Glenn Glaspie, Cassandra N. Miner, Michael D. Georgiou, Ioannis Y. Dance, Michael A. Louisiana State Univ Dept Oceanog & Coastal Sci Baton Rouge LA 70803 USA United States Fish & Wildlife Serv Baton Rouge Off Baton Rouge LA USA Water Inst New Orleans LA USA

Coastal restoration projects often require sediment resources borrowed from estuarine or marine ecosystems. A generalized additive modeling (GAM) framework was used to characterize fish-habitat relationships and predict spatiotemporal and ontogenetic shifts of Gulf sturgeon distri-bution within an impacted estuary in the northern Gulf of Mexico, Lake Pontchartrain. Habitat use and movement of Gulf sturgeon (n = 103) was monitored using an array of acoustic receivers (n = 81) from 2016 to 2019. Telemetry data was paired with environmental conditions hindcast from a high-resolution hydrodynamic model to develop GAMs for three life stages of Gulf stur-geon: juvenile, sub-adult, and adult. Model results demonstrated clear spatial, temporal, and ontogenetic shifts in habitat use for Gulf sturgeon in the Lake Pontchartrain estuary. The importance of spatial and temporal variables in the final models of all life stages suggests that distribution of Gulf sturgeon within the estuary is more likely driven by biology (prey distribu-tion) rather than environment. Interestingly, dependence of Gulf sturgeon on the estuary for overwintering habitat declined with ontogeny. The northeastern shoreline of Lake Pontchartrain was identified as potential nursery habitat for overwintering juvenile sturgeon from the Pearl River, while eastern portions of the estuary and associated channels provide critical staging habitat and corridors of connectivity for migrating sub-adult and adult sturgeon. Given the clear need to prioritize conservation of Gulf sturgeon while restoring coastal marshes, findings from this study provide needed information to shape future coastal restoration and inform the siting and timing of future dredging operations in Lake Pontchartrain.

关键词： Gulf sturgeon Lake Pontchartrain generalized additive models Habitat suitability Marsh creation Dredging

来源：评论

学校读者我要写书评

暂无评论

Body mass changes of dabbling and diving ducks wintering in California

引用

JOURNAL OF WILDLIFE MANAGEMENT 2024年第8期88卷

作者： Herzog, Mark P. Ackerman, Joshua T. Kohl, Jeffrey D. Fettig, Brady L. Hartman, C. Alex Peterson, Sarah H. Casazza, Michael L. Fleskes, Joseph P. US Geol Survey Western Ecol Res Ctr Dixon Field Stn 800 Business Pk DrSuite D Dixon CA 95620 USA

Bird body mass is often used as an index of body condition and fluctuates throughout the year in response to environmental conditions and avian life-history events. We examined the body mass of 59,572 ducks representing 13 species (7 dabbling duck species and 6 diving duck species) harvested within the 3 regions of the Central Valley in California, USA (Sacramento Valley, Suisun Marsh, San Joaquin Valley). Data collection occurred in winter during 5 hunting seasons (2014-2015, 2015-2016, 2017-2018, 2018-2019, 2019-2020). For all species, age, and sex classes, the body mass of dabbling ducks varied temporally and was lowest at the end of the hunting season in late January, declining from the beginning of the hunting season in mid-October (northern pintail [Anas acuta]: -11.4% to -20.4%;northern shoveler [Spatula clypeata]: -3.5% to -17.3%;cinnamon teal [Anas cyanoptera]: -5.0% to -17.1%;American wigeon [Mareca americana]: -6.9% to -12.2%;American green-winged teal [Anas carolinensis]: -5.9% to -11.9%;mallard [Anas platyrhynchos]: -1.8% to -9.6%;gadwall [Mareca strepera]: -2.2% to -8.4%). As expected, adults (after hatch-year) were heavier than immature (hatch-year) birds (within males: 0.6-8.6%;within females: 0.1-6.6%) and males were heavier than females (within adults: 3.1-38.6%;within immatures: 5.4-33.5%) at the end of the hunting season in all species. Within dabbling duck species, body masses did not differ among regions at the beginning of the hunting season but were heavier in the Sacramento Valley (0.5-14.4%) than other areas by the end of the hunting season. In contrast, body masses of diving ducks did not vary substantially during the hunting season or among regions. Diving ducks demonstrated inconsistent changes in mass from the beginning to the end of the season (lesser scaup [Aythya affinis]: 3.4% to 12.3%;canvasback [Aythya valisineria]: 5.1% to 6.1%;bufflehead [Bucephala albeola]: -3.2% to 1.6%;ring-necked duck [Aythya collaris]: -4.9% to 2.6%;common

关键词： Anas spp Aythya spp body condition generalized additive models wintering waterfowl

来源：评论

学校读者我要写书评

暂无评论

The Effects of Metronomic and Maximum-Tolerated Dose Chemotherapy in Colorectal Cancer Angiogenesis: A Combined Approach Using Endoscopic Diffuse Reflectance Spectroscopy and mRNA Expression

The Effects of Metronomic and Maximum-Tolerated Dose Chemoth...

引用

作者： Mundo Ortiz, Ariel Isaac University of Arkansas

学位级别：Ph.D., Doctor of Philosophy

Colorectal cancer (CRC) continues to be one of the most incident and deadliest types of cancer worldwide. Chemotherapy has proven effective to reduce tumor burden for CRC patients, but there are several disadvantages associated with the use of mainstay maximtolerated dose (MTD) chemotherapeutic strategies. Metronomic chemotherapy (MET) has been developed as an alternative that addresses the shortcomings of maximum-tolerated dose chemotherapy but so far its effectiveness as a neoadjuvant strategy for CRC has not been *** dissertation uses a combined optics and molecular biology approach (using diffuse reflectance spectroscopy and mRNA expression) to study the changes in angiogenesis and metabolism in primary colorectal tumors receiving MTD and MET. In Chapter 2, we first developed and validated a miniaturized spectroscopy probe that enabled the longitudinal investigation of changes in perfusion in primary tumors. Our results showed that an increase in oxygenation occurs in MET and MTD-treated tumors. In Chapter 3, we presented generalized additive models as an appropriate methodology to analyze the non-linear trends in longitudinal data that are commonly found in biomedical research. In Chapter 4, we sought to provide molecular context to the observed changes in perfusion from Chapter 2 by quantifying relative changes the expression of genes associated with angiogenesis. We found that despite eliciting a similar response, the molecular mechanisms behind increases in perfusion in MET and MTD-treated tumors are different. Specifically, tumors treated with MET presented higher Hif-1a, Aldoa and Pgk1 expression, indicating increased glycolytic activity. Taken together, this work highlights that the opportunities and challenges of MET to treat CRC can be better understood by using combined modalities that complement the information of changes caused by chemotherapy.

关键词： 5-fluorouracil Azoxymethane Colorectal cancer Diffuse reflectance spectroscopy generalized additive models Metronomic chemotherapy

来源：评论

学校读者我要写书评

暂无评论

Green spaces and mental health in the context of materialism: A comparative analysis before and during the COVID-19 pandemic

引用

URBAN FORESTRY & URBAN GREENING 2024年 102卷

作者： Tsurumi, Tetsuya Uchiyama, Yuta Sato, Masayuki Morioka, Mari Nanzan Univ Fac Policy Studies 18 Yamazato ChoShowa Ku Nagoya 4668673 Japan Kobe Univ Grad Sch Human Dev & Environm 3-11 TsurukabutoNada Ku Kobe 6578501 Japan

To investigate the potential change in the value of greenery due to increased time spent near homes during the COVID-19 pandemic, this study examined whether the relationship between green spaces within walking distance from homes and mental health has changed before and during the pandemic. Additionally, the study explored the potential shift to nonmaterialism during this period, assessing how this change in mindset might have influenced the relationship between greenery and mental health. According to our analysis, in March 2017 (before the pandemic), green spaces around residential areas showed a positive correlation with mental health for up to approximately 50 % green coverage rate;beyond this threshold, a negative correlation was observed. The analysis of March 2021 (during the pandemic) showed that green spaces around residential areas had a positive correlation with mental health for 0 % to approximately 50% green coverage, similar to the findings of March 2017. However, unlike 2017 results, no negative correlation was observed beyond 50% green coverage. Accordingly, we conclude that during the pandemic, people living in areas with relatively higher green coverage had better mental health compared to pre-pandemic levels. Additionally, a comparison between March 2017 and March 2021 indicated a general shift towards less materialistic attitudes. This shift might have contributed to mental health improvement during the COVID-19 crisis. If the trend toward nonmaterialistic thinking continues to rise over the long term, the benefits derived from green spaces are expected to increase.

关键词： Green space Mental health Materialism COVID-19 generalized additive models

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：