Extent and toxicity of contaminated marine sediments in Southeastern Florida

Thirty sites were sampled in southern Biscayne Bay and Manatee Bay in December 1999 to determine the extent of toxicity in sediments. Analyses and assays included: pesticides and phenols in seawater; chemical contaminants in sediment; amphipod mortality, HRGS P450, sea urchin sperm fertilization and embryology, MicrotoxTM, MutatoxTM, grass shrimp AChE and juvenile clam mortality assays; sea urchin sperm, amphipod and oyster DNA damage; and benthic community assessment. Sediment sites near the mouth of canals showed evidence of contamination. Contaminant plumes and associated toxicity do not appear to extend seaward of the mouth of the canals in an appreciable manner. Concentrations of contaminants in the sediments in open areas of Biscayne and Manatee Bays are generally low. (PDF contains 140 pages

Contaminant trends in US National Estuarine Research Reserves

Inputs of toxic chemicals provide one of the major types of anthropogenic stress threatening our Nation's coastal and estuarine waters. To assess this threat, the National Oceanic and Atmospheric Administration's (NOAA’s) National Status and Trends (NS&T) Program Mussel Watch Project monitors the concentrations of more than 70 toxic chemicals in sediments and on the whole soft-parts of mussels and oysters at over 300 sites around the U.S. Twenty of the 25 designated areas that comprise NOAA's National Estuarine Research Reserve System (NERRS) have one or more Mussel Watch monitoring sites. Trace elements and organic contaminants were quantified including As, Ag, Cd, Cu, Hg, Ni, Pb, Zn, ΣPCBs, ΣPAHs, DDT and its metabolites, and butyltins. The Mussel Watch sites located in or near the 20 Reserves provide for both status and trends. Generally the Reserves have trace element and organic contaminant concentrations that are at or below the median concentration determined for all NS&T Mussel Watch monitoring data. Trends were derived using the Spearman-rank correlation coefficient. It was possible to determine if trends exist for sites at which six or more years of data are available. Generally no trends were found for trace elements but when trends were found they were usually decreasing. The same general conclusion holds for organic contaminants but more decreasing trends were found than for trace elements. The greatest number of decreasing trends were found for tributyltin and its metabolites. (PDF contains 203 pages

An assessment of two decades of contaminant monitoring in the Nation’s Coastal Zone.

Executive Summary: Information found in this report covers the years 1986 through 2005. Mussel Watch began monitoring a suite of trace metals and organic contaminants such as DDT, PCBs and PAHs. Through time additional chemicals were added, and today approximately 140 analytes are monitored. The Mussel Watch Program is the longest running estuarine and coastal pollutant monitoring effort conducted in the United States that is national in scope each year. Hundreds of scientific journal articles and technical reports based on Mussel Watch data have been written; however, this report is the first that presents local, regional and national findings across all years in a Quick Reference format, suitable for use by policy makers, scientists, resource managers and the general public. Pollution often starts at the local scale where high concentrations point to a specific source of contamination, yet some contaminants such as PCBs are atmospherically transported across regional and national scales, resulting in contamination far from their origin. Findings presented here showed few national trends for trace metals and decreasing trends for most organic contaminants; however, a wide variety of trends, both increasing and decreasing, emerge at regional and local levels. For most organic contaminants, trends have resulted from state and federal regulation. The highest concentrations for both metal and organic contaminants are found near urban and industrial areas. In addition to monitoring throughout the nation’s coastal shores and Great Lakes, Mussel Watch samples are stored in a specimen bank so that trends can be determined retrospectively for new and emerging contaminants of concern. For example, there is heightened awareness of a group of flame retardants that are finding their way into the marine environment. These compounds, known as polybrominated diphenyl ethers (PBDEs), are now being studied using historic samples from the specimen bank and current samples to determine their spatial distribution. We will continue to use this kind of investigation to assess new contaminant threats. We hope you find this document to be valuable, and that you continue to look towards the Mussel Watch Program for information on the condition of your coastal waters. (PDF contains 118 pages

Spatial distribution of Chlorpyrifos and Endosulfan in USA coastal waters and the Great Lakes

Between 1994 and 1997, 258 tissue and 178 sediment samples were analyzed for chlorpyrifos throughout the coastal United States and the Great Lakes. Subsequently, 95 of the 1997 tissue samples were reanalyzed for endosulfan. Tissue chlorpyrifos concentrations, which exceeded the 90th percentile, were found in coastal regions known to have high agricultural use rates but also strongly correlated with sites near high population. The highest concentrations of endosulfans in contrast, were generally limited to agricultural regions of the country. Detections of chlorpyrifos at several Alaskan sites suggest an atmospheric transport mechanism. Many Great Lakes sites had chlorpyrifos tissue concentrations above the 90th percentile which decreased with increasing distance from the Corn Belt region (Iowa, Indiana, Illinois, and Wisconsin) where most agriculturally applied chlorpyrifos is used. Correlation analysis suggests that fluvial discharge is the primary transport pathway on the Atlantic and Gulf of Mexico coasts for chlorpyrifos but not necessarily for endosulfans. (PDF contains 28 pages

Expression of VPAC1 in a murine model of allergic asthma

Vasoactive intestinal polypeptide (VIP) is a putative neurotransmitter of the inhibitory non-adrenergic non-cholinergic nervous system and influences the mammalian airway function in various ways. Hence known for bronchodilatory, immunomodulatory and mucus secretion modulating effects by interacting with the VIP receptors VPAC1 and VPAC2, it is discussed to be a promising target for pharmaceutical intervention in common diseases such as COPD and bronchial asthma. Here we examined the expression and transcriptional regulation of VPAC1 in the lungs of allergic mice using an ovalbumin (OVA) -induced model of allergic asthma. Mice were sensitized to OVA and challenged with an OVA aerosol. In parallel a control group was sham sensitized with saline. VPAC1 expression was examined using RT-PCR and real time-PCR studies were performed to quantify gene transcription. VPAC1 mRNA expression was detected in all samples of OVA-sensitized and challenged animals and control tissues. Further realtime analysis did not show significant differences at the transcriptional level. Although the present studies did not indicate a major transcriptional regulation of VPAC1 in states of allergic airway inflammation, immunomodulatory effects of VPAC1 might still be present due to regulations at the translational level

The Impact of Stock Prices on Capital Structures: A Study on the German Stock Market

This thesis analyzes the corporate rebalancing behavior of German publicly listed firms subsequent to equity price shocks. The examined period (1990-2012) includes a total sample of 2,154 firm-years. It is found that German firms do not counteract stock induced changes in market-based capital ratios in the short run; whereas managerial rebalancing activity gradually gains importance in the long-term perspective. This behavior is largely in accordance with referential studies on the U.S. and the European stock markets. Further, a life-cycle extension of the applied research model has identified diverging rebalancing intensities across dissimilar corporate maturity classes. It was found, that those differences may be partly explained by respective adjustment cost levels

Wide-bandgap Semiconductors in Space: Appreciating the Benefits but Understanding the Risks

Dr. Jean-Marie Lauenstein, NASA Goddard Space Flight Center, will present the radiation challenges of adopting wide-bandgap semiconductors for space applications. Wide-bandgap devices are attractive for space applications due to improved performance such as faster switching speeds, lower power losses, and their ability to operate at higher temperature as compared with their silicon counterparts. Their tolerance to total ionizing dose levels (> 100 krad(Si)) further enhances the desirability of these technologies. This short course will focus on silicon carbide and gallium nitride power rectifying, switching, and RF devices as these technologies are now readily available commercially. The radiation hardness assurance issues presented by the heavy-ion radiation environment will be discussed

Research highlights from Regional Studies in Marine Science

publisher: Elsevier articletitle: Research highlights from Regional Studies in Marine Science journaltitle: Regional Studies in Marine Science articlelink: http://dx.doi.org/10.1016/j.rsma.2016.05.008 content_type: simple-article copyright: © 2016 Published by Elsevier B.V

Radiation Belt Modeling for Spacecraft Design: Model Comparisons for Common Orbits

We present the current status of radiation belt modeling, providing model details and comparisons with AP-8 and AE-8 for commonly used orbits. Improved modeling of the particle environment enables smarter space system design

Selektive Halogenierungen unter Phasentransferbedingungen: Mechanistische Untersuchungen und Synthetische Anwendungen

Die vorliegende Arbeit handelt von einer neuen selektiven Methode zur Halogenierung (Cl, Br, I) von organischen Verbindungen in Mehrphasensystemen. Durch die systematische Variation der Reaktionsbedingungen konnten starke Hinweise dafür gefunden werden, daß es sich bei dem Phasentransferprozess um einen Extraktionsmechanismus handelt. Weiterhin konnten durch Abfangexperimente sowie den Vergleich der experimentell bestimmten mit den computerberechneten kinetischen Isotopeneffekten auf einen radikalischen Mechanismus geschlossen werden, bei dem das Trihalomethylradikal für die Propagation der Kettenreaktion verantwortlich ist. Einige Vorteile dieser konzeptionell neuen Reaktion wurde anhand verschiedener Anwendungen unter Beweis gestellt. So konnte Cuban trotz seiner hohen Ringsapnnung unter Erhaltung der Käfigstruktur sowohl einfach als auch mehrfachhalogeniert werden, wodurch zum ersten Mal alle Regioisomere der Homodihalo- und Heterodiahloadamantane (Cl, Br, I) synthetisiert werden konnten. Der Grund für das außergewöhnliche Reaktionsverhalten des Trihalomethylradikals gegenüber Cuban und die Regioselektivität bei dessen Zweithalogenierung wurde durch Computerberechnungen nachvollzogen. Daß die Zweithalogenierungen ohne jeglichen Austausch eines bereits vorhandenen Halogenatoms verläuft, wurde bei der Synthese racemischer Gemische von unterschiedlich substituierter, chiraler Polyhaloadamantanverbindungen ausgenutzt. Die Racemate wurden durch chromatographische Methoden (GC, HPLC) sowohl analytisch als auch präparativ getrennt, nachdem eine Analyse mittels chiraler Verschiebungsreagenzien negativ verlief