Integrating Green Infrastructure Into Stormwater Policy: Reliability, Watershed Management, and Environmental Psychology as Holistic Tools for Success

As cities continue to expand, the issues of flood control and urban water quality have become major modern sustainability challenges. Green infrastructure—the use of nature-based solutions to target, treat, and store stormwater at its source—has emerged as a possible solution. While green infrastructure does offer multiple benefits for urban users, its performance is also highly variable. This Article addresses a key gap in existing literature by explicitly addressing how uncertainty in environmental and anthropogenic factors affects green infrastructure performance and integration within the Clean Water Act’s municipal separate storm sewer (MS4) regulatory program

Assessing the feasibility, cost, and utility of developing models of human performance in aviation

The purpose of the effort outlined in this briefing was to determine whether models exist or can be developed that can be used to address aviation automation issues. A multidisciplinary team has been assembled to undertake this effort, including experts in human performance, team/crew, and aviation system modeling, and aviation data used as input to such models. The project consists of two phases, a requirements assessment phase that is designed to determine the feasibility and utility of alternative modeling efforts, and a model development and evaluation phase that will seek to implement the plan (if a feasible cost effective development effort is found) that results from the first phase. Viewgraphs are given

Comparison of phosphatidylcholines containing one or two docosahexaenoic acyl chains on properties of phospholipid monolayers and bilayers

AbstractDocosahexaenoic acid (DHA) is the longest and most unsaturated of the n − 3 fatty acids found in membranes. Although a number of membrane properties have been demonstrated to be affected by the presence of this fatty acid, its mode of action has yet to be clearly elucidated. Prior reports on biological membranes have not distinguished the effect of mono-docosahexaenoyl phospholipids from those caused by phospholipids containing docosahexaenoic acid in both chains. This report compares properties of monolayers and bilayers composed of either 1-stearoyl-2-linolenoyl-sn-glycero-3-phosphocholine (as a control), 1-stearoyl-2-docosahexaenoyl-sn-glycero-3-phosphocholine or 1,2-di-docosahexaenoyl-sn-glycero-3-phosphocholine. When compared to the mono-DHA phosphatidylcholine (PC), the di-DHA PC occupies a much larger area/molecule, supports a more fluid and permeable bilayer, and is less susceptible to peroxidation. Monolayers made from either phospholipid are not condensable by cholesterol. We suggest many of the membrane properties linked to the presence of DHA may be the result of phospholipids which have lost their normal positional selectivity and have incorporated DHA into both positions

SPIN TRAPPING THE OXIDIZED PRODUCTS OF PUFA IN MODEL MEMBRANES: THE PROTECTION CONFERRED BY VITAMIN E

poster abstractElectron paramagnetic resonance (EPR) spectroscopy is recognized as the most sensitive and noninvasive means to quantify free radicals of biological relevance such as reactive oxygen species (ROS). In spin trapping a molecule (the spin trap) reacts with the free radical producing a spin adduct that is sufficiently stable to be detected by EPR. Here we apply a novel spin trapping technique to investigate the protection that α-tocopherol (vitamin E), the major lipid soluble antioxidant in membranes, confers on polyunsaturated lipids in model membranes. Polyunsaturated fatty acids (PUFA) readily oxidize because they have a cis,cis-1,4-pentadiene motif that renders the central methylene group vulnerable to attack by ROS. Our method quantifies the oxidized products of PUFA in lipid vesicles that have been exposed to a peroxyl radical generator 2,2'-azobis-(amidinopropane) dihydrochloride (AAPH) that initiates the free radical chain reaction. By measuring the reduction in lipid peroxidation due to the presence of αtocopherol, we test the hypothesis that the vitamin co-localizes with polyunsaturated lipids in membrane domains to ensure close proximity to the most vulnerable lipid species

DHA Alters Raft-like Membrane Domains as Revealed by Solid State 2H NMR Spectroscopy

poster abstractDietary omega-3 polyunsaturated fatty acids (n-3 PUFAs), such as docosahexaenoic acid (DHA, 22:6), are correlated with the prevention of neurological and autoimmune disorders in humans. These fatty acids must be obtained from the diet, such as oil fish or fish oil supplements, as they cannot be generated within the human body. The origin of the health benefits at the molecular level is still under question. A membrane-mediated mechanism in which n-3 PUFAs are incorporated into phospholipids and modulate molecular organization is one possibility. Cellular membranes are inhomogeneous where structurally diverse lipids can exist in separate domains. Regions rich in sphingomyelin (SM) and cholesterol, commonly called lipid rafts, contain important signaling proteins. In a recent solid-state 2H nuclear magnetic resonance (2H NMR) study of a model membrane composed of 1-[2H31] palmitoyl-2-docosahexaenoyl-phosphatidylcholine (PDPC-d31), a deuterated analog of a DHA-containing phospholipid, in mixtures with SM and cholesterol, we discovered that DHA could significantly enter raft-like domains. How DHA affects the molecular organization within the raft-like domains is addressed here by observing PSM-d31, an analog of SM with a perdeuterated N-palmitoyl chain. The 2H NMR spectra for PSM-d31, in mixtures with PDPC and cholesterol, exhibit two spectral components, a larger more ordered component that we attribute to raft-like domains and a smaller less ordered component that we attribute to non-raft-like domains. On average, the order of PSM-d31 is reduced and, thus, disordering of PSM-d31 by PDPC is indicated. Our observations confirm that DHA can infiltrate rafts and affect molecular organization, which has implications for the signaling of raft and non-raft proteins. Furthermore, these results are consistent with in vivo studies showing that DHA infiltrates rafts

Raft Busters: A Molecular Role for DHA in Biological Membranes?

poster abstractDietary consumption of fish oils rich in omega-3 polyunsaturated fatty acids (n-3 PUFAs), such as docosahexaenoic acid (DHA, 22:6), has a wide variety of health benefits. However, a complete molecular mechanism is yet to be elucidated. One model that has emerged from biochemical and imaging studies of cells postulates that n-3 PUFAs are taken up into phospholipids in the plasma membrane of cells and, due to their high disorder and aversion for cholesterol, reorganize lipid rafts. Lipid rafts are ordered domains within biological membranes which contain high amounts of sphingomyelin (SM) and cholesterol. To investigate this model, we studied lipid bilayers composed of SM, PDPC (a DHA-containing phospholipid), and cholesterol (1:1:1 mol). The molecular organization of each lipid was investigated with solid-state 2H NMR using deuterated analogs of the lipids. Spectral components assigned to ordered raft-like domains and disordered non-raft domains were resolved, from which the composition of the domains and the order within them could be determined. Most of the SM (84%) and cholesterol (88%) was found in the raft-like domain, together with a substantial amount of PDPC (70%). Despite the infiltration of PDPC there appears to be minimal effect on the order of SM or cholesterol. We speculate that PDPC molecules sequester into small groups minimizing the contact of DHA chains with cholesterol, thereby interrupting the continuity of the raft-like environment

DHA and EPA Interaction with Raft Domains Observed With Solid-State 2H NMR Spectroscopy

poster abstractResearch continues to examine the health benefits of omega-3 polyunsaturated fatty acids (n-3 PUFA) found in fish oils. The major bioactive components are eicosapentaenoic acid (EPA, 20:5), with 20 carbons and 5 double bonds, and docosahexaenoic acid (DHA, 22:6), with 22 carbons and 6 double bonds. However, their molecular modes of action remain unclear. A suggested hypothesis is that these fatty acids are incorporated into membrane phospholipids and modify the structure and organization of lipid rafts, thus affecting cell signaling. We used solid-state 2H NMR spectroscopy to compare molecular organization in mixtures of 1-palmitoyl-2-eicosapentaenoylphosphatidylcholine (PEPC) and 1-palmitoyl-2-docosahexaenoylphosphatidylcholine (PDPC) with the raft-stabilizing molecules sphingomyelin (SM) and cholesterol. Our spectra for PEPC-d31 and PDPC-d31, analogs of PEPC and PDPC with a perdeuterated palmitoyl sn-1 chain, showed that DHA has a greater tendency than EPA to incorporate into raft-like domains enriched in SM and cholesterol. By using PSM-d31, an analog of SM with a perdeuterated N-palmitoyl chain, we now directly observe one of the raft-forming molecules and analyze the molecular order within the raft. These results will add to the growing information on how EPA and DHA differentially modify lipid domain organization in bilayers

The Modular Group Action on Real SL(2)-characters of a One-Holed Torus

The group Gamma of automorphisms of the polynomial kappa(x,y,z) = x^2 + y^2 + z^2 - xyz -2 is isomorphic to PGL(2,Z) semi-direct product with (Z/2+Z/2). For t in R, Gamma-action on ktR = kappa^{-1}(t) intersect R displays rich and varied dynamics. The action of Gamma preserves a Poisson structure defining a Gamma-invariant area form on each ktR. For t < 2, the action of Gamma is properly discontinuous on the four contractible components of ktR and ergodic on the compact component (which is empty if t < -2). The contractible components correspond to Teichmueller spaces of (possibly singular) hyperbolic structures on a torus M-bar. For t = 2, the level set ktR consists of characters of reducible representations and comprises two ergodic components corresponding to actions of GL(2,Z) on (R/Z)^2 and R^2 respectively. For 2 < t <= 18, the action of Gamma on ktR is ergodic. Corresponding to the Fricke space of a three-holed sphere is a Gamma-invariant open subset Omega subset R^3 whose components are permuted freely by a subgroup of index 6 in Gamma. The level set ktR intersects Omega if and only if t > 18, in which case the Gamma-action on the complement ktR - Omega is ergodic.Comment: Published by Geometry and Topology at http://www.maths.warwick.ac.uk/gt/GTVol7/paper13.abs.html Note: Version 4 takes account of the referee's comments (version 3 was published in error

Do Facebook status updates reflect subjective well-being?

Ministry of Education, Singapore under its Academic Research Funding Tier