检索结果-内蒙古大学图书馆

Landsat-derived environmental factors to describe habitat preferences and spatiotemporal distribution of phytoplankton

引用

ECOLOGICAL MODELLING 2019年 408卷

作者： Angel Matus-Hernandez, Miguel Octavio Martinez-Rincon, Raul Judith Avina-Hernandez, Rosa Yolanda Hernandez-Saavedra, Norma Ctr Invest Biol Noroeste La Paz 23205 Bcs Mexico CONACYT Ctr Invest Biol Noroeste La Paz Bcs Mexico

Phytoplankton species are among the most abundant and diverse organisms in marine ecosystems and are highly sensitive to physical-chemical variable changes, so they show high spatial and temporal variability related to environmental changes. This study applied generalized additive models (GAM) to describe the effect of environmental factors on abundance of four phytoplankton genera recorded in a small coastal water body of northwestern Mexico. The most influential variables in order of importance were sea surface temperature, chlorophyll-a concentration, pH, salinity and dissolved oxygen. Predictions of the GAM suggested that abundance had strong spatial and seasonal variability;abundance of Tripos and Gymnodinium was higher in spring (Apr-Jun) and lower in summer (Jul-Sep);Prorocentrum was higher in autumn (Oct-Dec) and lower in winter (Jan-Mar);Pseudo-nitzschia was higher in winter and lower in autumn. The approach in this study represents one of the first efforts to use species distribution models (SDM) in phytoplankton communities using high spatial resolution environmental factors that derived from Landsat imagery. Therefore, this technique could be a useful tool with the potential to transform environmental monitoring and serve as a valuable resource in the study and application of management strategies in a wide range of activities in coastal environments, such as aquaculture, fisheries and public health.

关键词： Species distribution models Phytoplankton Coastal environment Landsat 8 generalized additive models

来源：评论

学校读者我要写书评

暂无评论

Analysis of nonlinear associations between prenatal methylmercury exposure from fish consumption and neurodevelopmental outcomes in the Seychelles Main Cohort at 17 years

引用

STOCHASTIC ENVIRONMENTAL RESEARCH AND RISK ASSESSMENT 2018年第4期32卷 893-904页

作者： Huang, Li-Shan Cory-Slechta, Deborah A. Cox, Christopher Thurston, Sally W. Shamlaye, Conrad F. Watson, Gene E. van Wijngaarden, Edwin Zareba, Grazyna Strain, J. J. Myers, Gary J. Davidson, Philip W. Natl Tsing Hua Univ Inst Stat 101 Kuang Fu Rd Sect 2 Hsinchu 30013 Taiwan Univ Rochester Sch Med & Dent Dept Biostat & Computat Biol Rochester NY 14627 USA Univ Rochester Dept Environm Med Sch Med & Dent Rochester NY USA Univ Rochester Eastman Dept Dent Sch Med & Dent Rochester NY USA Univ Rochester Dept Community & Prevent Med Sch Med & Dent Rochester NY USA Univ Rochester Dept Neurol Sch Med & Dent Rochester NY USA Univ Rochester Dept Pediat Sch Med & Dent Rochester NY USA Johns Hopkins Bloomberg Sch Publ Hlth Dept Epidemiol Baltimore MD USA Minist Hlth Victoria Seychelles Univ Ulster Coleraine Londonderry North Ireland

The Seychelles Child Development Study has been examining the relationship between prenatal methylmercury (MeHg) exposure from consuming fish during pregnancy and child development. This study re-analyzes seven outcomes in the 17 year Main Cohort data to determine if there are nonlinear or non-homogeneous (subgroup) associations that were not identified in the linear analysis. We adopted two statistical approaches. First, we carried out an additive nonlinear analysis assuming homogeneous prenatal MeHg-outcome relationships to explore overall associations. Second, we applied the regression tree to the Woodcock-Johnson Calculation subtest (it was significantly associated in earlier analyses) and identified 4 clusters based on covariates. Then we used additive models to assess the prenatal MeHg association in each of the four clusters for all seven outcomes. This approach assumes nonlinear associations in each cluster and non-homogeneous associations between clusters. The additive nonlinear analysis yielded prenatal MeHg curves similar to the linear analysis. For the regression tree analysis, the curves relating prenatal MeHg to outcomes between the 4 clusters differed and some crossed at higher prenatal MeHg levels, suggesting non-homogeneity in the upper range of exposure. Additionally, some of the curves suggested a possible non-linear relationship within the range of exposure we studied. This non-linear analysis supports the findings from the linear analysis. It shows little evidence to support an adverse association of prenatal MeHg exposure through maternal consumption of fish contaminated with natural background levels. However, the tree analysis suggests that the prenatal exposure/outcome relationship may not be homogeneous across all individuals and that some subpopulations may have an adverse association in the upper range of the exposures studied. More robust data in the higher levels of exposure in this cohort are needed to confirm this finding.

关键词： Child development Methylmercury generalized additive models Prenatal exposure Regression tree

来源：评论

学校读者我要写书评

暂无评论

Application of data-driven models in the analysis of marine power systems

引用

APPLIED OCEAN RESEARCH 2019年 92卷

作者： Swider, Anna Langseth, Helge Pedersen, Eilif Rolls Royce Marine AS Kongsberg CM AS Alesund Norway Norwegian Univ Sci & Technol NTNU Dept Marine Technol Trondheim Norway Norwegian Univ Sci & Technol NTNU Dept Comp Sci Trondheim Norway

Utilization of measurements from on board monitoring systems of marine vessels is a part of shipbuilding industry's digitalization phase. The data collected can be used to verify and improve vessel's power system design. Deployment of data-driven statistical models can enhance the knowledge about the power requirements. In this study, we describe a data-driven statistical model that can be used to study and analyze the power requirement of a vessel, which might help to understand the key factors that influence the power and to quantify their contribution. We propose a powerful tool namely, generalized additive model (GAM), which allows us to model nonlinearities. We build the GAM to see the relationship between power consumed and the key influential factors for a power system based on real data from a platform supply vessel (PSV) in a dynamic positioning (DP) mode with diesel-electric configuration. We also describe the importance of feature extraction based on Hilbert Transform to improve the model. In addition, we fit the linear regression (LR) model as a reference model. In the last phase we verify the results of GAM, LR with simulation model from ShipX to show that the data-driven model is within the boundaries of power requirement from simulations.

关键词： Statistical modeling generalized additive models GAM Linear regression Power system Power requirement Power system dimensioning Station-keeping Vessel motions Hilbert transform

来源：评论

学校读者我要写书评

暂无评论

Investigating the Behaviour of Human Thermal Indices under Divergent Atmospheric Conditions: A Sensitivity Analysis Approach

引用

ATMOSPHERE 2019年第10期10卷

作者： Charalampopoulos, Ioannis Nouri, Andre Santos Agr Univ Athens Lab Gen & Agr Meteorol Iera Odos 75 Athens 11855 Greece Polo Univ Alto da Ajuda Univ Lisbon Fac Architecture Rua Sa Nogeuira P-1349063 Lisbon Portugal

This paper aims to analyse and conclude about the behaviour of the most commonly used human thermal comfort indices under a variety of atmospheric conditions in order to provide further information about their appropriateness. Utilising generalized additive models (GAMs), this article examines the indices' sensitivity when exposed to diverse classified atmospheric conditions. Concentrated upon analysing commonly used human thermal indices, two Statistical/Algebraic indices (Thermohygrometric Index (THI) and HUMIDEX (HUM)), and four Energy Balance Model indices (Physiologically Equivalent Temperature (PET), modified PET (mPET), Universal Thermal Climate Index (UTCI), and Perceived Temperature (PT)) were selected. The results of the study are twofold, the identification of (1) index sensitivity to parameters' variation, and change rates, resultant of different atmospheric conditions;and, (2) the overall pertinence of each of the indices for local thermal comfort evaluation. The results indicate that the thermohygrometric indices cannot follow and present the thermal conditions' variations. On the other hand, UTCI is very sensitive under low radiation condition, and PET/mPET present higher sensitivity when the weather is dominated by high radiation and air temperature. PT index provides the lower sensitive among the human energy balance indices, but this is adequately sensitive to describe the thermal comfort environment.

关键词： human thermal comfort bioclimatic indices urban climate and biometeorology generalized additive models R-language sensitivity analysis

来源：评论

学校读者我要写书评

暂无评论

A simple function for full-subsets multiple regression in ecology with R

引用

ECOLOGY AND EVOLUTION 2018年第12期8卷 6104-6113页

作者： Fisher, Rebecca Wilson, Shaun K. Sin, Tsai M. Lee, Ai C. Langlois, Tim J. Australian Inst Marine Sci UWA Oceans Inst Crawley WA Australia Univ Western Australia UWA Oceans Inst Crawley WA Australia Univ Western Australia Sch Biol Sci Crawley WA Australia Dept Pk & Wildlife Marine Sci Program Kensington WA Australia Natl Univ Singapore Trop Marine Sci Inst Singapore Singapore

Full-subsets information theoretic approaches are becoming an increasingly popular tool for exploring predictive power and variable importance where a wide range of candidate predictors are being considered. Here, we describe a simple function in the statistical programming language R that can be used to construct, fit, and compare a complete model set of possible ecological or environmental predictors, given a response variable of interest and a starting generalized additive (mixed) model fit. Main advantages include not requiring a complete model to be fit as the starting point for candidate model set construction (meaning that a greater number of predictors can potentially be explored than might be available through functions such as dredge);model sets that include interactions between factors and continuous nonlinear predictors;and automatic removal of models with correlated predictors (based on a user defined criterion for exclusion). The function takes continuous predictors, which are fitted using smoothers via either gam, gamm (mgcv) or gamm4, as well as factor variables which are included on their own or as two-level interaction terms within the gam smooth (via use of the by argument), or with themselves. The function allows any model to be constructed and used as a null model, and takes a range of arguments that allow control over the model set being constructed, including specifying cyclic and linear continuous predictors, specification of the smoothing algorithm used, and the maximum complexity allowed for smooth terms. The use of the function is demonstrated via case studies that highlight how appropriate model sets can be easily constructed and the broader utility of the approach for exploratory ecology.

关键词： collinearity complete-subsets modeling gam generalized additive models information theoretic approaches multimodel inference multiple regression

来源：评论

学校读者我要写书评

暂无评论

Spatial analyses of ALS incidence in Denmark over three decades

引用

AMYOTROPHIC LATERAL SCLEROSIS AND FRONTOTEMPORAL DEGENERATION 2018年第3-4期19卷 275-284页

作者： Vieira, Veronica M. Hansen, Johnni Gredal, Ole Weisskopf, Marc G. Danish Canc Soc Res Ctr Copenhagen Denmark Natl Rehabil Ctr Neuromuscular Disorders Copenhagen Denmark Harvard TH Chan Sch Publ Hlth Dept Environm Hlth Boston MA USA Harvard TH Chan Sch Publ Hlth Dept Epidemiol Boston MA USA

Objective: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease of the motor neuron with very few known risk factors. We conducted a spatial epidemiologic analysis of ALS incidence in Denmark to assess the contribution of sociodemographic determinants to geographic variation. Methods: We analyzed 4249 ALS cases (1982-2013), each with 100 controls matched on sex and birth year. Odds ratio and 95% confidence bands at birth and diagnosis/index locations were calculated using generalized additive models. We included a bivariate spatial smooth for location in our conditional logistic regression adjusted for socioeconomic status and marital status. We also conducted analyses adjusted for both birth and diagnosis addresses to separate location effects. Results: We observed significantly elevated ALS odds near Copenhagen for both the birth and diagnosis period analyses. Sociodemographic factors did not explain the observed patterns. When we further adjusted our spatial analyses by including both birth and diagnosis addresses, the significant area of elevated male ALS odds by birth address shifted to northwest Denmark away from Copenhagen, and there was little evidence of variation among women. Geographic variation at diagnosis differed between male and females, suggesting that patterns are not just due to regional variation in case ascertainment. Conclusion: ALS incidence in Denmark is associated with both location at birth and diagnosis, suggesting that geographic variation may be due to exposures occurring at birth or closer to diagnosis, although the latter could relate to case ascertainment issues.

关键词： Amyotrophic lateral sclerosis spatial analysis generalized additive models

来源：评论

学校读者我要写书评

暂无评论

Modeling the distribution and abundance of eastern tur (Capra cylindricornis) in the Caucasus

引用

JOURNAL OF MAMMALOGY 2018年第4期99卷 885-897页

作者： Gavashelishvili, Alexander Yarovenko, Yuriy A. Babayev, Elmar A. Mikeladze, Giorgi Gurielidze, Zurab Dekanoidze, Davit Kerdikoshvili, Niko Ninua, Levan Paposhvili, Nika Ilia State Univ Inst Ecol Ctr Biodivers Studies Cholokashvili Str 5 GE-0162 Tbilisi Georgia RASci Daghestan Sci Ctr Precaspian Inst Biol Resources Moscow Russia Ilia State Univ Inst Ecol Program Ecol & Conservat Large Mammals Cholokashvili Str 5 GE-0162 Tbilisi Georgia

Our research attempts 1) to link the distribution and abundance of eastern tur (Capra cylindricornis) to environmental variables varying in space and time, and 2) to identify environmental constraints that may have caused the geographic segregation of eastern tur from western tur (Capra caucasica). Our results suggest that 1) eastern tur are heat-sensitive but prefer snow-free, grass-dominated areas near escape cliffs, and in terrain that is difficult for humans and livestock to reach;and 2) present-day genetic and phenotypic differences between the Capra species are largely related to discontinuity of and impeded migration between Capra populations during glacial periods, and insufficient time in the postglacial period for now-adjoining Capra populations to overcome behavioral mechanisms impeding hybridization in the wild so as to erase these differences.

关键词： abundance biome Capra spp. distribution generalized additive models glacial refugium LGM

来源：评论

学校读者我要写书评

暂无评论

Describing temporal change in adult female Lepeophtheirus salmonis abundance on Scottish farmed Atlantic salmon at the national and regional levels

引用

AQUACULTURE 2018年 489卷 148-153页

作者： Hall, L. M. Murray, A. G. Marine Scotland Sci Aberdeen AB11 9DB Scotland

Patterns of change over time for adult female Lepeophtheirus salmonis abundance on Scottish farmed Atlantic salmon, Salmo salar, from December 2010 to September 2017 inclusive at the national level and four constituent regions are described. The analysis comprises a generalized additive Model on summary statistics published by the Scottish Salmon Producers' Organisation. Irregular within-year oscillations were detected at the national level and for three regions. Non-linear longer-term changes at the national level and for two regions were also detected with no apparent overall increase occurring over the period. The results from this analysis are compared to those from a previous analysis utilising a linear model on a subset of the data. We conclude that the GAM provides an improved description of the temporal changes of this parasite.

关键词： Aquaculture Sea lice generalized additive models Time

来源：评论

学校读者我要写书评

暂无评论

Influence of oceanographic conditions on the distribution and abundance of blackfin tuna (Thunnus atlanticus) larvae in the Gulf of Mexico

引用

FISHERIES RESEARCH 2018年 201卷 1-10页

作者： Cornic, Maelle Rooker, Jay R. Texas A&M Univ Dept Marine Biol Galveston Campus1001 Texas Clipper Rd Galveston TX 77554 USA Texas A&M Univ Dept Wildlife & Fisheries Sci College Stn TX 77843 USA

Information on early life history of economical important fisheries stocks are required to accurately estimate their population status. This study investigated blackfin tuna (Thunnus atlanticus) larvae distribution over six summers (2007-2011, 2015) in the northern Gulf of Mexico. Blackfin tuna were commonly observed and widely distributed in surface waters with frequency of occurrence ranging from 48% (2008) to 92% (2011). Inter annual variability in density was observed with highest mean density recorded in 2009 (17.2 larvae 1000 m(-3)) and lowest mean density in 2015 (2.2 larvae 1000 m(-3)). Density also varied between months with higher overall mean density observed in July (9.2 larvae 1000m(-3)) compared to June (4.3 larvae 1000m(-3)). generalized additive models (GAMs) based on presence/absence and density of blackfin tuna larvae determined that this species was present in areas of intermediate salinity (31-36) and higher sea surface temperature (SST > 29 degrees C). Blackfin tuna larvae were also strongly associated with convergent zones near the Loop Current and anticyclonic eddies. Environmental conditions deemed to be favorable from GAMs (salinity, SST and sea surface height) were combined with environmental data in 2011 and 2015 to predict the suitable habitat of blackfin tuna larvae from the outer continental shelf into oceanic waters (areas >= 100 m isobath). The amount of highly suitable habitat ( > 10 larvae 1000m(-3)) in 2011 and 2015 varied between months (June 6%, July 51%);however, blackfin tuna larvae were predicted to occur at similar locations in surface waters along the continental slope and at the margin of the Loop Current. Overall, the results highlighted the importance of mesoscale features and oceanographic conditions on the distribution and abundance of blackfin tuna larvae.

关键词： Larvae generalized additive models Oceanographic features

来源：评论

学校读者我要写书评

暂无评论

Habitat supply for Yellow Perch (Actinopterygii, Percidae) varies with space, time, and life stage in Lake Erie

引用

HYDROBIOLOGIA 2018年第1期808卷 371-386页

作者： Liu, Changdong Jiao, Yan Reid, Kevin B. Tang, Yanli Ma, Shuyang Ocean Univ China Dept Fisheries Qingdao Shandong Peoples R China Virginia Polytech Inst & State Univ Dept Fish & Wildlife Conservat Blacksburg VA 24061 USA Univ Guelph Dept Integrat Biol Guelph ON N1G 2W1 Canada

Exploring species-environment relationships to identify essential habitat areas is recognized as an effective way for resource conservation and management. Because of ecological and economic importance of Yellow Perch (Perca flavescens) in Lake Erie, it is essential to develop appropriate habitat models to analyze habitat supply of this species. Empirical species-environment models for two age-groups (juveniles and adults) at two depth strata were developed based on a long-term (27 years) gillnet survey data. models incorporated interactive terms indicate a high degree of prediction accuracy and satisfied the assumption of residual independence. As a benthivorous species, high-quality habitat is mainly distributed in the bottom waters. Suitable habitat for adults is also found in the mid-waters in the central and east basins. Weighted suitability index per unit area differs significantly among years, basins, and vertical strata. Currently, quota allocation among jurisdictions is determined by using GIS applications of jurisdictional surface area of waters within each management unit. The outputs from our study can be used to revise the current quota allocation schemes and habitat-based quota allocation protocol will provide more scientific and rational total allowable catch for each jurisdiction.

关键词： Perca flavescens Habitat suitability indices generalized additive models Interaction terms Habitat distribution

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：