5,734 research outputs found

    Developing Offset Banking Systems in Georgia

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    Offset banking involves a public or private entity investing in a project that has the effect of substantially reducing a targeted pollutant(s), such as sediment runoff, phosphorus, heavy metals, etc. This project is referred to as "the bank." The entity creating the bank receives "credits" for the associated reduction in pollutants, which it can then sell to publically-owned treatment works (POTWs) or other point source polluters facing high costs of meeting discharge standards. Trades can be allowed on a 1-to-1 basis: the buyer obtains one credit for each creditequivalent increase in pollution associated with his/her activities; or higher trading ratios can be required, e.g., 3:1, where the buyer must acquire (in this example) three credits for each creditequivalent increase in pollution associated with his/her activities. In this latter case trades result in actual environmental improvements.This paper addresses two major issues. The first refers to the steps required to establish a pilot project for one or more offset banking projects in Georgia. These steps are: identifying entities with incentives to purchase offset credits; identifying one or more entities that might establish a bank, and potential bank sites; establishing trading rules with appropriate local water quality management authorities; and obtaining approval of the proposed trading program from the U.S. EPA.The second major issue addressed in the paper is means by which an offset bank might be created. For this purpose, a brief survey is offered of existing water quality trading projects in the U.S.. Buyers of offset credits are virtually always point-source polluters (POTWs or industries). Point and non-point projects have been used as "banks" -- as a source for offset banking credits. Attention in this paper is focused on non-point sources that might serve as banks for pilot offset banking projects in Georgia. Both low- and high-technology alternatives that might be used for such projects are discussed.Notwithstanding incentive-related limitations on the number of point source polluters that might constitute the "demand" for offset credits discussed in section II, the authors have identified one entity (Fulton County) that may represent significant demand for credits, and they expect to identify others. Moreover, the authors argue that continued growth in Georgia, particularly in the Atlanta and Coastal areas of the State, will give rise to sufficient numbers of point source entities seeking new discharge permits to warrant interest in offset banking as a means of meeting increasingly stringent discharge restrictions at minimum cost. If or when enforcement of TMDLs gains strength in the State, needs for systems like offset banking will increase accordingly. These considerations, and the associated benefits to Georgians that might attend the establishment of offset banking programs in the State, serve as the rationale for the author's continued interest in exploring means by which pilot offset banking projects can be established in Georgia. Working Paper # 2003-00

    Indestructibility of Vopenka's Principle

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    We show that Vopenka's Principle and Vopenka cardinals are indestructible under reverse Easton forcing iterations of increasingly directed-closed partial orders, without the need for any preparatory forcing. As a consequence, we are able to prove the relative consistency of these large cardinal axioms with a variety of statements known to be independent of ZFC, such as the generalised continuum hypothesis, the existence of a definable well-order of the universe, and the existence of morasses at many cardinals.Comment: 15 pages, submitted to Israel Journal of Mathematic

    Situation Normality and the Shape of Search: The Effects of Time Delays and Information Presentation on Search Behavior

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    Delays have become one of the most often cited complaints of web users. Long delays often cause users to abandon their searches, but how do tolerable delays affect information search behavior? Intuitively, we would expect that tolerable delays should induce decreased information search. We conducted two experiments and found that as delay increased, a point occurs at which time within-page information search increases; that is, search behavior remained the same until a tipping point occurs where delay increases the depth of search. We argue that situation normality explains this phenomenon; users have become accustomed to tolerable delays up to a point (our research suggests between 7 and 11 s), after which search behavior changes. That is, some delay is expected, but as delay becomes noticeable but not long enough to cause the abandonment of search, an increase occurs in the “stickiness” of webpages such that users examine more information on each page before moving to new pages. The net impact of tolerable delays was counterintuitive: tolerable delays had no impact on the total amount of data searched in the first experiment, but induced users to examine more data points in the second experiment

    Dynamics of manganese, cadmium, and lead in experimental power plant ponds

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    This study was designed to determine the effect of heated power plant cooling water on the compartmentalization of manganese, lead and cadmium in experimental ponds. Caged channel catfish and green sunfish were kept in an experimental pond and a control pond. Periodically, whole fishes, gill, heart, kidney, liver and musculature were analyzed for the three metals. Concentrations of the three metals in fishes were not affected by the temperature differential maintained during the study. There was no correlation in concentrations of cadmium and lead with age (weight and length) of fishes but manganese concentrations declined slightly with age. The water component of the system contained the lowest concentration of the metals with sediments acting as a characteristic sink. Concentrations of the three metals in water and sediments of the ponds were unaffected by heat inasmuch as concentration differences between ponds were not significant at the .05 level. Aquatic organisms such as snails, fingernail clams, leeches, tubificid annelids and dragonfly nymphs exhibited concentrations of cadmium higher than sediments while snails and duckweed more closely reflected concentrations of manganese in sediments. Tubificid worms and leeches more closely reflected lead concentrations in sediments while fingernail clams and snails exhibited higher concentrations.U.S. Department of the InteriorU.S. Geological SurveyOpe

    The early X-ray afterglows of optically bright and dark Gamma-Ray Bursts

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    A systematical study on the early X-ray afterglows of both optically bright and dark gamma-ray bursts (B-GRBs and D-GRBs) observed by Swift has been presented. Our sample includes 25 GRBs. Among them 13 are B-GRBs and 12 are D-GRBs. Our results show that the distributions of the X-ray afterglow fluxes (FXF_{X}), the gamma-ray fluxes (SγS_{\gamma}), and the ratio (Rγ,XR_{\gamma, X}) for both the D-GRBs and B-GRBs are similar. The differences of these distributions for the two kinds of GRBs should be statistical fluctuation. These results indicate that the progenitors of the two kinds of GRBs are the same population. Their total energy explosions are comparable. The suppression of the optical emissions from D-GRBs should results from circumburst but not their central engine.Comment: 10 pages, 3 figures, 1 table; accepted by ChJA

    Cardinal characteristics at in a small u (κ) model

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    We provide a model where u(κ)<2κu(κ)<2κ for a supercompact cardinal κ. [10] provides a sketch of how to obtain such a model by modifying the construction in [6]. We provide here a complete proof using a different modification of [6] and further study the values of other natural generalizations of classical cardinal characteristics in our model. For this purpose we generalize some standard facts that hold in the countable case as well as some classical forcing notions and their properties

    Fetal membrane bacterial load is increased in histologically confirmed inflammatory chorioamnionitis: A retrospective cohort study

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    Introduction It is widely debated whether fetal membranes possess a genuine microbiome, and if bacterial presence and load is linked to inflammation. Chorioamnionitis is an inflammation of the fetal membranes. This research focussed on inflammatory diagnosed histological chorioamnionitis (HCA) and aimed to determine whether the bacterial load in fetal membranes correlates to inflammatory response, including histological staging and inflammatory markers in HCA. Methods Fetal membrane samples were collected from patients with preterm spontaneous labour and histologically phenotyped chorioamnionitis (HCA; n = 12), or preterm (n = 6) and term labour without HCA (n = 6). The bacterial profile of fetal membranes was analysed by sequencing the V4 region of the 16S rRNA gene. Bacterial load was determined using qPCR copy number/mg of tissue. The association between bacterial load and bacterial profile composition was assessed using correlation analysis. Results Bacterial load was significantly greater within HCA amnion (p = 0.002) and chorion (p = 0.042), compared to preterm birth without HCA. Increased bacterial load was positively correlated with increased histological staging (p = 0.001) and the expression of five inflammatory markers; IL8, TLR1, TLR2, LY96 and IRAK2 (p=<0.050). Bacterial profiles were significantly different between membranes with and without HCA in amnion (p = 0.012) and chorion (p = 0.001), but no differences between specific genera were detected. Discussion Inflammatory HCA is associated with infection and increased bacterial load in a dose response relationship. Bacterial load is positively correlated with HCA severity and the TLR signalling pathway. Further research should investigate the bacterial load threshold required to generate an inflammatory response in HCA
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