2,819 research outputs found

    Molecular Size Distributions of Heavy Metals in Lake Washington

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    Four untreated and one magnesium treated water samples from Lake Washington, the potable water source for the city of Melbourne, Florida, were collected and analyzed for As, Cd, Cr, Cu, Fe, Pb, Ni, Zn, Mb, Ca, and color on the basis of molecular weight distribution. Molecular weight distributions of the samples were obtained using a Millipore ultrafiltration system and filters in the following sizes: 106, 105, 2.5 x 104, 104, and 103 nominal molecular weight limits (nmwl). Color causing materials in the untreated samples were found to be located in the molecular weight fraction greater than 2.5 x 104 nmwl. The majority of the metals concentrations (approximately greater than 80%) were also found to be located in the molecular weight fraction greater than 2.5 x 104 nmwl. Analysis of the magnesium treated (for maximum color removal) sample showed higher concentrations of metals passing the respective filter sizes as opposed to the untreated samples indicating less complexation or smaller molecular complexes of the metals. Thus, a fairly strong correlation between heavy metals concentrations and color in the Lake Washington samples was indicated

    Polynomial Identities, Indices, and Duality for the N=1 Superconformal Model SM(2,4\nu)

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    We prove polynomial identities for the N=1 superconformal model SM(2,4\nu) which generalize and extend the known Fermi/Bose character identities. Our proof uses the q-trinomial coefficients of Andrews and Baxter on the bosonic side and a recently introduced very general method of producing recursion relations for q-series on the fermionic side. We use these polynomials to demonstrate a dual relation under q \rightarrow q^{-1} between SM(2,4\nu) and M(2\nu-1,4\nu). We also introduce a generalization of the Witten index which is expressible in terms of the Rogers false theta functions.Comment: 41 pages, harvmac, no figures; new identities, proofs and comments added; misprints eliminate

    Analytic Tableaux for Simple Type Theory and its First-Order Fragment

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    We study simple type theory with primitive equality (STT) and its first-order fragment EFO, which restricts equality and quantification to base types but retains lambda abstraction and higher-order variables. As deductive system we employ a cut-free tableau calculus. We consider completeness, compactness, and existence of countable models. We prove these properties for STT with respect to Henkin models and for EFO with respect to standard models. We also show that the tableau system yields a decision procedure for three EFO fragments

    Outcomes of acute intraoperative surgical conversion during endovascular aortic aneurysm repair

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    PurposeOutcomes and predictors of acute surgical conversion during endovascular aortic aneurysm repair (EVAR) were examined using the American College of Surgeons-National Safety and Quality Improvement Project (ACS-NSQIP) Database (2005 to 2008).MethodsAcute intraoperative surgical conversions occurring during elective EVAR were identified using Current Procedural Terminology codes. Nonemergent EVAR and primary open surgical repairs of infrarenal aneurysms were examined for comparison. Perioperative morbidity was categorized as wound, pulmonary, venous thromboembolic, genitourinary, cardiovascular, operative, and septic. Mortality, overall morbidity, and length of stay (LOS) were examined.ResultsWe identified 72 acute conversions, 2414 open repairs, and 6332 EVAR without acute conversion. Demographics and comorbidities were generally similar among operative groups. Mean operative time was 274 minutes for acute conversion vs 226 minutes for primary open repair and 162 minutes for EVAR (conversion vs EVAR and open repair vs EVAR P < .0001 for each; conversion vs open repair P = .0014; analysis on rank operative time). Blood transfusion was required in 69% of acute conversions (mean volume, 6.0 units) vs 73% of open repairs (mean volume, 3.3 units) and 12% of EVARs (mean volume, 2.6 units; P < .0001 for each pair-wise comparison; analysis on rank number of units among those transfused). Major morbidity was 28% for acute conversions, 28% for open repairs, and 12% for EVARs. Mortality was 4.2% for acute conversions, 3.2% for open repairs, and 1.3% for EVARs. Median (quartile 1, quartile 3) LOS was 7 (5, 9) days for acute conversion and open repair, and 2 (1, 3) days for EVAR. Morbidity and mortality were significantly higher for acute conversion and open repair vs EVAR. The OR (95% confidence interval) for morbidity was 2.9 (1.7-4.8) after conversion and 2.8 (2.5-3.2) after open repair (P < .0001 for both) and for mortality was 3.4 (1.0-10.9; P = .0437) for conversion and 2.5 (1.9-3.5; P < .0001) for open repair. Morbidity and mortality were similar between acute conversion and open repair. A similar pattern among repair groups was demonstrated for LOS, with similar LOS for acute conversions and open repair, which were significantly longer than those observed for EVAR. No significant demographic or medical risk factor predictors of acute conversion during EVAR were identified.ConclusionAcute surgical conversion was a rare complication affecting 1.1% of EVAR cases, with no broadly identifiable at-risk population. When conversion did occur, morbidity and mortality rates paralleled those observed for elective open repair

    The Bivariate Rogers-Szeg\"{o} Polynomials

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    We present an operator approach to deriving Mehler's formula and the Rogers formula for the bivariate Rogers-Szeg\"{o} polynomials hn(x,yq)h_n(x,y|q). The proof of Mehler's formula can be considered as a new approach to the nonsymmetric Poisson kernel formula for the continuous big qq-Hermite polynomials Hn(x;aq)H_n(x;a|q) due to Askey, Rahman and Suslov. Mehler's formula for hn(x,yq)h_n(x,y|q) involves a 3ϕ2{}_3\phi_2 sum and the Rogers formula involves a 2ϕ1{}_2\phi_1 sum. The proofs of these results are based on parameter augmentation with respect to the qq-exponential operator and the homogeneous qq-shift operator in two variables. By extending recent results on the Rogers-Szeg\"{o} polynomials hn(xq)h_n(x|q) due to Hou, Lascoux and Mu, we obtain another Rogers-type formula for hn(x,yq)h_n(x,y|q). Finally, we give a change of base formula for Hn(x;aq)H_n(x;a|q) which can be used to evaluate some integrals by using the Askey-Wilson integral.Comment: 16 pages, revised version, to appear in J. Phys. A: Math. Theo

    Growth of plasmonic nanoparticles for aging cask-matured whisky

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    The maturation of spirit in wooden casks is key to the production of whisky, a hugely popular and valuable product, with the transfer and reaction of molecules from the wooden cask with the alcoholic spirit imparting color and flavor. However, time in the cask adds significant cost to the final product, requiring expensive barrels and decades of careful storage. Thus, many producers are concerned with what “age” means in terms of the chemistry and flavor profiles of whisky. We demonstrate here a colorimetric test for spirit “agedness” based on the formation of gold nanoparticles (NPs) by whisky. Gold salts were reduced by barrel-aged spirit and produce colored gold NPs with distinct optical properties. Information from an extinction profile, such as peak position, growth rate, or profile shape, was analyzed, and our assay output was correlated with measurements of the whisky sample makeup, assays for key functional groups, and spiking experiments to explore the mechanism in more detail. We conclude that age is not just a number, that the chemical fingerprint of key flavor compounds is a useful marker for determining whisky “age”, and that our simple reduction assay could assist in defining the aged character of a whisky and become a useful future tool on the warehouse floor
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