Physical Sciences and Mathematics Commons^™

Piecewisesem: Piecewise Structural Equation Modelling In R For Ecology, Evolution, And Systematics, Jonathan S. Lefcheck

VIMS Articles

Summary

1. Ecologists and evolutionary biologists rely on an increasingly sophisticated set of statistical tools to describe complex natural systems. One such tool that has gained significant traction in the biological sciences is structural equation models (SEM), a form of path analysis that resolves complex multivariate relationships among a suite of interrelated variables.

2. Evaluation of SEMs has historically relied on covariances among variables, rather than the values of the data points themselves. While this approach permits a wide variety of model forms, it limits the incorporation of detailed specifications. Recent developments have allowed for the simultaneous implementation of non‐normal distributions, random …

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Decadal Re-Evaluation Of Contaminant Exposure And Productivity Of Ospreys (Pandion Haliaetus) Nesting In Chesapeake Bay Regions Of Concern, Rs Lazarus, Ba Rattner, Pc Mcgowan, Robert Hale, Et Al

VIMS Articles

The last large-scale ecotoxicological study of ospreys (Pandion haliaetus) in Chesapeake Bay was conducted in 2000-2001 and focused on U.S. EPA-designated Regions of Concern (ROCs; Baltimore Harbor/Patapsco, Anacostia/middle Potomac, and Elizabeth Rivers). In 2011-2012, ROCs were re-evaluated to determine spatial and temporal trends in productivity and contaminants. Concentrations of p,p'-DDE were low in eggs and below the threshold associated with eggshell thinning. Eggs from the Anacostia/middle Potomac Rivers had lower total PCB concentrations in 2011 than in 2000; however, concentrations remained unchanged in Baltimore Harbor. Polybrominated diphenyl ether flame retardants declined by 40%, and five alternative brominated flame retardants were …

Historical Summer Distribution Of The Endangered North Atlantic Right Whale (Eubalaena Glacialis): A Hypothesis Based On Environmental Preferences Of A Congeneric Species, Sophie Monserrat, Maria G. Pennino, Tim D. Smith, Randall R. Reeves, Christine N. Meynard, David M. Kaplan, Ana S.L. Rodrigues

VIMS Articles

Aim: To obtain a plausible hypothesis for the historical distribution of North Atlantic right whales (NARWs) (Eubalaena glacialis) in their summer feeding grounds. Previously widespread in the North Atlantic, after centuries of hunt- ing, these whales survive as a small population off eastern North America. Because their exploitation began before formal records started, information about their historical distribution is fragmentary.

Modeling Storm Surge And Inundation In Washington, Dc, During Hurricane Isabel And The 1936 Potomac River Great Flood, Harry V. Wang, Jon Derek Loftis, David R. Forrest, Wade Smith, Barry Stamey

VIMS Articles

Abstract: Washington, DC, the capital of the U.S., is located along the Upper Tidal Potomac River, where a reliable operational model is needed for making predictions of storm surge and river-induced flooding. We set up a finite volume model using a semi-implicit, Eulerian-Lagrangian scheme on a base grid (200 m) and a special feature of sub-grids (10 m), sourced with high-resolution LiDAR data and bathymetry surveys. The model domain starts at the fall line and extends 120 km downstream to Colonial Beach, VA. The model was used to simulate storm tides during the 2003 Hurricane Isabel. The water level measuring …

Representing Taxonomic, Phylogenetic And Functional Diversity: New Challenges For Mediterranean Marine-Protected Areas, Francois Guilhaumon, Camille Albouy, Et Al, Christine N. Meynard

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To assess gaps in the representation of taxonomic, phylogenetic and func- tional diversity among coastal fishes in Mediterranean marine-protected areas (MPAs).

Scientific Evidence Supports A Ban On Microbeads, Cm Rochman, Sm Kross, Jb Armstrong, Mt Bogan, Es Darling, Sj Green, Ar Smyth, D Verissimo

VIMS Articles

No abstract provided.

Regression Or Significance Tests: What Other Choice Is There?-An Academic Perspective Response, Mc Newman, M Krull

VIMS Articles

Both the no-observed-effect concentration and its null hypothesis significance testing foundation have drawn steady criticism since their inceptions [1–5]. Many in our field reasonably advocate regression to avoid conventional null hypothesis significance testing shortcomings; however, regression is compromised under commonly encountered conditions (Green,present Perspective’s Challenge). As the debate to favor null hypothesis significance testing or regression methods continues into the 21st century, a sensible strategy might be to take a moment to ask, Are there now other choices? Our goal is to sketch out 1 such choice.