Recommendations to Increase the Resilience of Wastewater Treatment in Coastal Virginia

This white paper discusses the problem of septic failures in Virginia, as infrastructure ages and previously installed systems can no longer function. Section II.A. discusses the feasibility of regulatory and other measures that the Virginia state and local governments can implement to incentivize the identification, maintenance and repair of septic systems. Among these measures is a point-of-sale inspection requirement, which would require real property sellers to have their septic system inspected upon sale. Additionally, this white paper addresses several alternative options to conventional onsite septic systems, including public information campaigns to inform septic system owners of maintenance and repair techniques; and programs incentivizing the creation and use of innovative septic systems as alternatives to conventional systems. Section II.C examines eligibility for aid based on different federal metrics of hardship and discusses options to increase the number of people eligible for aid. The Virginia General Assembly has created grant and loan programs to address the growing septic problem, and the Virginia Department of Health has received federal funding to assist with septic and private well repairs as well. This white paper also discusses the potential environmental justice and equitable concerns raised by the implementation of various programs and proposes some septic options. Adopting any or a combination of these options could improve the longevity and resiliency of septic systems as well as homeowner awareness of emerging issues. This abstract has been taken from the authors\u27 introduction

Velocity profiles in shear-banding wormlike micelles

Using Dynamic Light Scattering in heterodyne mode, we measure velocity profiles in a much studied system of wormlike micelles (CPCl/NaSal) known to exhibit both shear-banding and stress plateau behavior. Our data provide evidence for the simplest shear-banding scenario, according to which the effective viscosity drop in the system is due to the nucleation and growth of a highly sheared band in the gap, whose thickness linearly increases with the imposed shear rate. We discuss various details of the velocity profiles in all the regions of the flow curve and emphasize on the complex, non-Newtonian nature of the flow in the highly sheared band.Comment: 4 pages, 5 figures, submitted to Phys. Rev. Let

Plant sphingolipids: their importance in cellular organization and adaption

Sphingolipids and their phosphorylated derivatives are ubiquitous bio-active components of cells. They are structural elements in the lipid bilayer and contribute to the dynamic nature of the membrane. They have been implicated in many cellular processes in yeast and animal cells, including aspects of signaling, apoptosis, and senescence. Although sphingolipids have a better defined role in animal systems, they have been shown to be central to many essential processes in plants including but not limited to, pollen development, signal transduction and in the response to biotic and abiotic stress. A fuller understanding of the roles of sphingolipids within plants has been facilitated by classical biochemical studies and the identification of mutants of model species. Recently the development of powerful mass spectrometry techniques hailed the advent of the emerging field of lipidomics enabling more accurate sphingolipid detection and quantitation. This review will consider plant sphingolipid biosynthesis and function in the context of these new developments. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner

The Gelfand problem for the 1-homogeneous p-Laplacian

In this paper, we study the existence of viscosity solutions to the Gelfand problem for the 1-homogeneous p-Laplacian in a bounded domain Ω ⊂ ℝN, that is, we deal with − 1 p − 1|∇u|2−p div(|∇u|p−2∇u) = λeu in Ω with u = 0 on ∂Ω. For this problem we show that, for p ∈ [2, ∞], there exists a positive critical value λ∗ = λ∗(Ω, N, p) such that the following holds: ∙ If λ < λ∗, the problem admits a minimal positive solution wλ. ∙ If λ > λ∗, the problem admits no solution. Moreover, the branch of minimal solutions {wλ} is increasing with λ. In addition, using degree theory, for fixed p we show that there exists an unbounded continuum of solutions that emanates from the trivial solution u = 0 with λ = 0, and for a small fixed λ we also obtain a continuum of solutions with p ∈ [2, ∞].The first author was partially supported by MINECO–FEDER Grant MTM2015-68210-P (Spain) and Junta de Andalucía FQM-194 (Spain). The second author was partially supported by MINECO–FEDER Grant MTM2015-68210-P (Spain), Junta de Andalucía FQM-116 (Spain) and MINECO Grant BES-2013- 066595 (Spain). The third author was partially supported by CONICET (Argentina) and MINECO–FEDER Grant MTM2015-70227-P (Spain)

Cohomological tautness for Riemannian foliations

In this paper we present some new results on the tautness of Riemannian foliations in their historical context. The first part of the paper gives a short history of the problem. For a closed manifold, the tautness of a Riemannian foliation can be characterized cohomologically. We extend this cohomological characterization to a class of foliations which includes the foliated strata of any singular Riemannian foliation of a closed manifold

A performance prediction model for pumps as turbines (PATs)

In recent years, the interest towards the use of pumps operating as turbines (PATs) for the generation of electrical energy has increased, due to the low cost of implementation and maintenance. The main issue that inhibits a wider use of PATs is the lack of corresponding characteristic curves, because manufacturers usually provide only the pump-mode performance characteristics. In the PAT selection phase, the lack of turbine-mode characteristic curves forces users to expend expensive and time-consuming efforts in laboratory testing. In the technical literature, numerous methods are available for the prediction of PAT turbine-mode performance based on the pump-mode characteristics, but these models are usually calibrated making use of few devices. To overcome this limit, a performance database called Redawn is presented and the data collected are used to calibrate novel PAT performance models

Variability in marsh migration potential determined by topographic rather than anthropogenic constraints in the Chesapeake Bay region

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molino, G. D., Carr, J. A., Ganju, N. K., & Kirwan, M. L. Variability in marsh migration potential determined by topographic rather than anthropogenic constraints in the Chesapeake Bay region. Limnology and Oceanography Letters, 7(4), (2022): 321-331, https://doi.org/10.1002/lol2.10262.Sea level rise (SLR) and saltwater intrusion are driving inland shifts in coastal ecosystems. Here, we make high-resolution (1 m) predictions of land conversion under future SLR scenarios in 81 watersheds surrounding Chesapeake Bay, United States, a hotspot for accelerated SLR and saltwater intrusion. We find that 1050–3748 km2 of marsh could be created by 2100, largely at the expense of forested wetlands. Predicted marsh migration exceeds total current tidal marsh area and is ~ 4× greater than historical observations. Anthropogenic land use in marsh migration areas is concentrated within a few watersheds and minimally impacts calculated metrics of marsh resilience. Despite regional marsh area maintenance, local ecosystem service replacement within vulnerable watersheds remains uncertain. However, our work suggests that topography rather than land use drives spatial variability in wetland vulnerability regionally, and that rural land conversion is needed to compensate for extensive areal losses on heavily developed coasts globally.This work was funded by the U.S. Geological Survey Climate Research and Development and the U.S. Geological Survey Coastal and Marine Hazards and Resources Program. Additional funding was provided from the National Science Foundation CAREER, LTER, and CZN programs (EAR-1654374, DEB-1832221, and EAR-2012670)