2,250 research outputs found

    Vaginal yeasts in the era of "over the counter" antifungals

    Get PDF
    OBJECTIVE: To establish whether there has been any rise in the prevalence of non-albicans Candida species isolated from vaginal swabs since the introduction of “over the counter” antifungal treatments. METHOD: A retrospective review looking at all positive vaginal yeast isolates collected from women attending one genitourinary medicine clinic during the 6 year period from 1993 to 1998 inclusive. All positive vaginal yeast isolates were included, regardless of whether or not the patients were symptomatic. Isolates from HIV positive women were excluded from the analysis. RESULT: No increase in non-albicans vaginal yeast isolates was shown during the period studied. The proportion of non-albicans yeasts remained constant at approximately 5% of the total yeasts isolated. The most common non-albicans yeast isolated was C glabrata. CONCLUSION: There is no evidence from this study to suggest that the increasing use of “over the counter” antifungal treatment has selected for atypical, possibly inherently azole resistant, strains of vaginal yeasts in HIV seronegative women

    Azumaya loci and discriminant ideals of PI algebras

    Get PDF
    We prove that, under mild assumptions, for all positive integers ℓ, the zero set of the discriminant ideal D ℓ (R/Z(R), tr)of a prime aïŹƒne polynomial identity (PI) algebra R coincides with the zero set of the modiïŹed discriminant ideal MD ℓ (R/Z(R), tr) of R, and give an explicit description of this set in terms of the dimensions of the irreducible representations of R. Furthermore, we prove that, when ℓ is the square of the PI-degree of R, this zero set is precisely the complement of the Azumaya locus of R. This description is used to classify the Azumaya loci of the multiparameter quantized Weyl algebras at roots of unity. As another application, we prove that the zero set of the top discriminant ideal of a prime aïŹƒne PI algebra R coincides with the singular locus of the center of R, provided that the discriminant ideal has height at least 2, R has ïŹnite global dimension and R is a Cohen–Macaulay module over its center

    Fluctuations of the Retarded Van der Waals Force

    Get PDF
    The retarded Van der Waals force between a polarizable particle and a perfectly conducting plate is re-examined. The expression for this force given by Casimir and Polder represents a mean force, but there are large fluctuations around this mean value on short time scales which are of the same order of magnitude as the mean force itself. However, these fluctuations occur on time scales which are typically of the order of the light travel time between the atom and the plate. As a consequence, they will not be observed in an experiment which measures the force averaged over a much longer time. In the large time limit, the magnitude of the mean squared velocity of a test particle due to this fluctuating Van der Waals force approaches a constant, and is similar to a Brownian motion of a test particle in an thermal bath with an effective temperature. However the fluctuations are not isotropic in this case, and the shift in the mean square velocity components can even be negative. We interpret this negative shift to correspond to a reduction in the velocity spread of a wavepacket. The force fluctuations discussed in this paper are special case of the more general problem of stress tensor fluctuations. These are of interest in a variety of areas fo physics, including gravity theory. Thus the effects of Van der Waals force fluctuations serve as a useful model for better understanding quantum effects in gravity theory.Comment: 14 pages, no figure

    Passenger transmission and productiveness of transit lines with high loads

    Get PDF
    Deterministic transit capacity analysis applies to planning, design and operational management of urban transit systems. The Transit Capacity and Quality of Service Manual (1) and Vuchic (2, 3) enable transit performance to be quantified and assessed using transit capacity and productive capacity. This paper further defines important productive performance measures of an individual transit service and transit line. Transit work (p-km) captures the transit task performed over distance. Passenger transmission (p-km/h) captures the passenger task delivered by service at speed. Transit productiveness (p-km/h) captures transit work performed over time. These measures are useful to operators in understanding their services’ or systems’ capabilities and passenger quality of service. This paper accounts for variability in utilized demand by passengers along a line and high passenger load conditions where passenger pass-up delay occurs. A hypothetical case study of an individual bus service’s operation demonstrates the usefulness of passenger transmission in comparing existing and growth scenarios. A hypothetical case study of a bus line’s operation during a peak hour window demonstrates the theory’s usefulness in examining the contribution of individual services to line productive performance. Scenarios may be assessed using this theory to benchmark or compare lines and segments, conditions, or consider improvements

    Natural variation of the nef gene in human immunodeficiency virus type 2 infections in Portugal

    Get PDF
    Human immunodeficiency virus type 2 (HIV-2) infections cause severe immunodeficiency in humans, although HIV-2 is associated frequently with reduced virulence and pathogenicity compared to HIV-1. Genetic determinants that play a role in HIV pathogenesis are relatively poorly understood but nef has been implicated in inducing a more pathogenic phenotype in vivo. However, relatively little is known about the role of nef in HIV-2 pathogenesis. To address this, the genetic composition of 44 nef alleles from 37 HIV-2-infected individuals in Portugal, encompassing a wide spectrum of disease associations, CD4 counts and virus load, has been assessed. All nef alleles were subtype A, with no evidence of gross deletions, truncations or disruptions in the nef-encoding sequence; all were full-length and intact. HIV-2 long terminal repeat sequences were conserved and also indicated subtype A infections. Detailed analysis of motifs that mediate nef function in HIV-1 and simian immunodeficiency virus, such as CD4 downregulation and putative SH2/SH3 interactions, revealed significant natural variation. In particular, the central P(104)xxPLR motif exhibited wide interpatient variation, ranging from an HIV-1-like tetra-proline structure (PxxP)(3) to a disrupted minimal core motif (P(104)xxQLR). The P(107)-->Q substitution was associated with an asymptomatic phenotype (Fisher's exact test, P=0.026) and low virus loads. These data indicate that discrete differences in the nef gene sequence rather than gross structural changes are more likely to play a role in HIV-2 pathogenesis mediated via specific functional interactions

    Non-holomorphic multi-matrix gauge invariant operators based on Brauer algebra

    Full text link
    We present an orthogonal basis of gauge invariant operators constructed from some complex matrices for the free matrix field, where operators are expressed with the help of Brauer algebra. This is a generalisation of our previous work for a signle complex matrix. We also discuss the matrix quantum mechanics relevant to N=4 SYM on S^{3} times R. A commuting set of conserved operators whose eigenstates are given by the orthogonal basis is shown by using enhanced symmetries at zero coupling.Comment: 29 pages, typos corrected, references adde

    Finite gravitational action for higher derivative and stringy gravities

    Get PDF
    We generalize the local surface counterterm prescription suggested in Einstein gravity for higher derivative (HD) and Weyl gravities. Explicitly, the surface counterterm is found for three- and five-dimensional HD gravities. As a result, the gravitational action for asymptotically AdS spaces is finite and gravitational energy-momentum tensor is well-defined. The holographic trace anomaly for d2 and d4 boundary (gauge) QFT dual to above HD gravity is calculated from gravitational energy-momentum tensor. The calculation of AdS black hole mass in HD gravity is presented within above prescrition. The comparison with the standard prescription (using reference spacetime) is done.Comment: LaTeX file, 21 page

    UK export performance research - review and implications

    Get PDF
    Previous research on export performance has been criticized for being a mosaic of autonomous endeavours and for a lack of theoretical development. Building upon extant models of export performance, and a review and analysis of research on export performance in the UK for the period 1990-2005, an integrated model of export performance is developed and theoretical explanations of export performance are put forward. It is suggested that a multi-theory approach to explaining export performance is viable. Management and policy implications for the UK emerging from the review and synthesis of the literature and the integrated model are discussed

    Effect of Used Lubricating Oil Contaminated Soil on Seed Germination and Early Growth Performance of Wild -Type Legume, Crotalaria retusa L.

    Get PDF
    Contamination of soil due to used lubricating oil (ULO) has become a common environmental issue, especially in major cities worldwide. This may affect negatively on overall soil quality and may pose a risk to biota. Phytoremediation is a novel green technological approach, which uses plants to remove organic and inorganic pollutants from contaminated soil, air and water and can be usefully used to clean up ULO contaminated soil. Screening of plant species with tolerance to ULO contamination is the most critical initial step in phytoremediation. The aim of the present study is to evaluate tolerance of Crotalaria retusa L. to ULO-contaminated soil. Germination of C. retusa seeds in soils with 1-5% w/w ULO contamination levels was tested according to the ISO method, with five replicates per treatment and ten seeds per replicate. Percentage inhibition of seed germination, root growth and biomass were measured at 48 and 72 hours of incubation. Results showed 100% seed germination in the control (uncontaminated soil) and all treatments indicating high tolerance of tested seeds to germinate in ULO-contaminated soil. However, there was a significant (p<0.05) reduction in root length of seedlings in all treatments above 3% w/w ULO. Therefore, a further pot experiment was carried out using ULO contamination levels of 0.5%, 1%, 1.5%, 2%, 2.5% and 3% w/w ULO. A fully randomized block design (RBD) was employed with 4 replicates per treatment and control. Percentage biodegradation of ULO and shoot height were measured monthly and at the end of a three month exposure chlorophyll a, b, total chlorophyll content, shoot height, root length, shoot system biomass and root system biomass were all measured. Results indicated time-dependent increases in percentage biodegradation of different treatments. At three months, percentage biodegradation was 52.2%, 43.8%, 35.6%, 32.2%, 25.2% and 22.0% for the 0.5-3.0% w/w ULO treatments, respectively. A decrease in growth parameters was observed with an increase in ULO contamination levels. However, the calculated IC50values inferred that the substantial negative effects resulted only on plants grown in soil with contamination levels greater than 2% w/w. There were no significant differences in chlorophyll contents of seedlings under any treatments. Therefore, from the present study we can conclude that C. retusa is able to grow in soils contaminated with ULO up to a level of 2% w/w without showing any negative effects. This result highlights the potential of C. retusa for the phytoremediation of ULO contaminated soil.Keywords: Crotalaria retusa, Phytoremediation, Used lubricant oilAcknowledgements: National Research Council, Sri Lanka (Grant No. 16-144) for financial assistanc
    • 

    corecore