1,233 research outputs found

    New tool gauges impact of exchange rates on states

    Get PDF
    States with relatively more employment tied to international trade are increasingly likely to be sensitive to exchange rate movements, and face sharply different effective exchange rate shifts, often provoked by economic or financial crises. ; Analysts need a tool to more effectively gauge the sometimes varied impact of exchange rate movements on states. In this article, we introduce a measure that compares the value of the dollar against the currencies of countries with which each of the 50 states trade--the real trade-weighted value of the dollar (RTWVD) index. ; To assess the impact of exchange rates on states, the RTWVD weights the U.S. dollar exchange rate with various countries based on a state's share of exports. It is a "real" measure because it adjusts the exchange rate for different rates of inflation. The index will allow analysts to more precisely identify the exchange rates that most affect a state's economy.International trade ; Foreign exchange rates ; Exports

    Z3_3-graded differential geometry of quantum plane

    Full text link
    In this work, the Z3_3-graded differential geometry of the quantum plane is constructed. The corresponding quantum Lie algebra and its Hopf algebra structure are obtained. The dual algebra, i.e. universal enveloping algebra of the quantum plane is explicitly constructed and an isomorphism between the quantum Lie algebra and the dual algebra is given.Comment: 17 page

    A square root of the harmonic oscillator

    Get PDF
    Allowing for the inclusion of the parity operator, it is possible to construct an oscillator model whose Hamiltonian admits an EXACT square root, which is different from the conventional approach based on creation and annihilation operators. We outline such a model, the method of solution and some generalizations.Comment: RevTex, 10 pages in preprint form, no figure

    Efficient estimation of AUC in a sliding window

    Full text link
    In many applications, monitoring area under the ROC curve (AUC) in a sliding window over a data stream is a natural way of detecting changes in the system. The drawback is that computing AUC in a sliding window is expensive, especially if the window size is large and the data flow is significant. In this paper we propose a scheme for maintaining an approximate AUC in a sliding window of length kk. More specifically, we propose an algorithm that, given ϵ\epsilon, estimates AUC within ϵ/2\epsilon / 2, and can maintain this estimate in O((logk)/ϵ)O((\log k) / \epsilon) time, per update, as the window slides. This provides a speed-up over the exact computation of AUC, which requires O(k)O(k) time, per update. The speed-up becomes more significant as the size of the window increases. Our estimate is based on grouping the data points together, and using these groups to calculate AUC. The grouping is designed carefully such that (ii) the groups are small enough, so that the error stays small, (iiii) the number of groups is small, so that enumerating them is not expensive, and (iiiiii) the definition is flexible enough so that we can maintain the groups efficiently. Our experimental evaluation demonstrates that the average approximation error in practice is much smaller than the approximation guarantee ϵ/2\epsilon / 2, and that we can achieve significant speed-ups with only a modest sacrifice in accuracy

    Characterization of a human liver carboxylesterase (hCE-1) that catalyzes the hydrolysis of cocaine to benzoylecgonine and the formation of cocaethylene from alcohol and cocaine

    Get PDF
    This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department ([email protected])

    Representation-theoretic derivation of the Temperley-Lieb-Martin algebras

    Get PDF
    Explicit expressions for the Temperley-Lieb-Martin algebras, i.e., the quotients of the Hecke algebra that admit only representations corresponding to Young diagrams with a given maximum number of columns (or rows), are obtained, making explicit use of the Hecke algebra representation theory. Similar techniques are used to construct the algebras whose representations do not contain rectangular subdiagrams of a given size.Comment: 12 pages, LaTeX, to appear in J. Phys.

    Characterization of actinomycetes antagonistic to Phytophthora fragariae var. rubi, the causal agent of raspberry root rot

    Get PDF
    Onze souches d'actinomycetes ayant la capacité de protéger les plants de framboisiers (Rubus strigosus) contre les infections causées par les Phytophthora ont été caractérisées. Il a été montré que toutes les souches appartenaient au genre Streptomyces. Deux souches (EF-34 et EF-76) croissaient à 4, 15 et 30°C sur un milieu V8 agar dont le pH avait été ajusté entre 5 et 9. Sept souches dont EF-34 et EF-76 pouvaient hydrolyser les parois cellulaires de Phytophthora et inhiber la croissance du champignon à 15°C et à des pH variant entre 5 et 9. Toutes les souches inhibaient la croissance du P. fragariae var. rubi et du Pythium ultimum. La croissance d'autres espèces fongiques et de bactéries à Gram négatif n'était inhibée qu'en présence de trois souches (EF-14, EF-72 et EF-76). Les onze actinomycetes antagonistes ont été classés en quatre groupes selon leur résistance à divers pesticides utilisés pour protéger les cultures de framboisiers. La souche EF-76 a été caractérisée plus en détail. Cette souche a été identifiée comme étant le Streptomyces hygroscopicus var. geldanus, et produisait l'antibiotique geldanamycine.Eleven actinomycete strains that were previously shown to protect raspberry (Rubus strigosus) plants against Phytophthora infection were characterized. all were shown to belong to the genus Streptomyces. Two strains (EF-34 and EF-76) grew at 4, 15 and 30°C on V8 agar between pHs 5 to 9. Seven strains including EF-34 and EF-76 had both the ability to hydrolyze Phytophthora cell walls and to inhibit Phytophthora growth at 15°C between pHs 5 to 9. all actinomycetes inhibited the growth of P. fragariaevar. rubi and of Pythium ultimum. The growth of other fungal species and of Gram-negative bacteria was inhibited only in the presence of three strains (EF-14, EF-72, and EF-76). The eleven antagonistic actinomycetes were classified into four groups with regard to their resistance to various pesticides used to protect raspberry crops. Strain EF-76 was further characterized. This strain was identified as Streptomyceshygroscopicus var. geldanus, and it was shown to produce geldanamycin, a known antibiotic

    Lixiviação de íons potássio, cálcio e magnésio para determinação do vigor em sementes de milho doce.

    Get PDF
    O teste de lixiviação de íons de potássio, cálcio e magnésio é baseado na integridade das membranas celulares das sementes, sendo considerado um procedimento rápido para a avaliação do vigor em sementes de várias espécies. Porém, para sementes de milho doce não se têm informações necessárias para a validação deste procedimento. Com isso, o trabalho teve como objetivo obter informações que permitam o aperfeiçoamento dos testes de lixiviação de potássio, cálcio e magnésio para a avaliação do vigor em sementes de milho doce. Foram utilizados 14 lotes de sementes de milho doce de duas cultivares, BR-401 e BR-402. O delineamento utilizado foi inteiramente casualizado com três repetições. A qualidade fisiológica das sementes foi avaliada por meio dos testes de germinação, condutividade elétrica, emergência a campo, lixiviação de potássio, de cálcio e de magnésio. Os testes de lixiviação de potássio e magnésio foram eficientes na avaliação do vigor em sementes de milho doce. A condutividade elétrica apresentou correlação negativa com a emergência de plântulas e positiva com a lixiviação de íons de potássio e magnésio

    Biogeochemical responses to late-winter storms in the Sargasso Sea, III—Estimates of export production using 234Th:238U disequilibria and sediment traps

    Get PDF
    Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 56 (2009): 875-891, doi:10.1016/j.dsr.2009.01.008.Direct measurements of new production and carbon export in the subtropical North Atlantic Ocean appear to be too low when compared to geochemical based estimates. It has been hypothesized that episodic inputs of new nutrients into surface water via the passage of mesoscale eddies or winter storms may resolve at least some of this discrepancy. Here, we investigated particulate organic carbon (POC), particulate organic nitrogen (PON), and biogenic silica (BSiO2) export using a combination of water column 234Th:238U disequilibria and free-floating sediment traps during and immediately following two weather systems encountered in February and March 2004. While these storms resulted in a 2-4 fold increase in mixed layer NO3 inventories, total chlorophyll a and an increase in diatom biomass, the systems was dominated by generally low 234Th:238U disequilibria, suggesting limited particle export. Several 234Th models were tested, with only those including non-steady state and vertical upwelling processes able to describe the observed 234Th activities. Although upwelling velocities were not measured directly in this study, the 234Th model suggests reasonable rates of 2.2 to 3.7 m d-1. Given the uncertainties associated with 234Th derived particle export rates and sediment traps, both were used to provide a range in sinking particle fluxes from the upper ocean during the study. 234Th particle fluxes were determined applying the more commonly used steady state, 1-dimensional model with element/234Th ratios measured in sediment traps. Export fluxes at 200 m ranged from 1.91 ± 0.20 to 4.92 ± 1.22 mmol C m-2 d-1, 0.25 ± 0.08 to 0.54 ± 0.09 mmol N m-2 d-1, and 0.22 ± 0.04 to 0.50 ± 0.06 mmol Si m-2 d-1. POC export efficiencies (Primary Production/Export) were not significantly different from the annual average or from time periods without storms, although absolute POC fluxes were elevated by 1-11%. This increase was not sufficient, however, to resolve the discrepancy between our observations and geochemical based estimates of particle export. Comparison of PON export rates with simultaneous measurements of NO3 - uptake derived new production rates, suggested that only a fraction, < 35%, of new production was exported as particles to deep waters during these events. Measured bSiO2 export rates were more than a factor of two higher (p < 0.01) than the annual average, with storm events contributing as much as 50% of annual bSiO2 export in the Sargasso Sea. Furthermore it appears that 65 - 95% (average 86 ± 14%) of the total POC export measured in this study was due to diatoms. Combined these results suggest that winter storms do not significantly increase POC and PON export to depth. Rather, these storms may play a role in the export of bSiO2 to deep waters. Given the slower remineralization rates of bSiO2 relative to POC and PON, this transport may, over time, slowly decrease water column silicate inventories, and further drive the Sargasso Sea towards increasing silica limitation. These storm events may further affect the quality of the POC and PON exported given the large association of this material with diatoms during these periods.This study was funded by the National Science Foundation (Chemical Oceanography Grants OCE-0244612 and OCE-0241645)
    corecore