381 research outputs found

    Local and global persistence exponents of two quenched continuous lattice spin models

    Full text link
    Local and global persistence exponents associated with zero temperature quenched dynamics of two dimensional XY model and three dimensional Heisenberg model have been estimated using numerical simulations. We have used the method of block persistence to find both global and local exponents simultaneously (in a single simulation). Temperature universality of both the exponents for three dimensional Heisenberg model has been confirmed by simulating the stochastic (with noise) version of the equation of motion. The noise amplitudes added were small enough to retain the dynamics below criticality. In the second part of our work we have studied scaling associated with correlated persistence sites in the three dimensional Heisenberg model in the later stages of the dynamics. The relevant length scale associated with correlated persistent sites was found to behave in a manner similar to the dynamic length scale associated with the phase ordering dynamics.Comment: 20 pages, 7 figure

    A Survival-Adjusted Quantal-Response Test for Analysis of Tumor Incidence Rates in Animal Carcinogenicity Studies

    Get PDF
    In rodent cancer bioassays, groups of animals are exposed to different doses of a chemical of interest and followed for tumor occurrence. The resulting tumor rates are commonly analyzed using a survival-adjusted Cochran-Armitage (CA) trend test. The CA trend test has reasonable power when the tumor-response curve is linear in dose, but it may be underpowered for a nonlinear response. An alternative survival-adjusted test procedure based on isotonic regression methodology has previously been proposed. Although this alternative procedure performs well when the tumor response is nonlinear in dose, it has less power than the CA trend test when the response is linear in dose. Here, we introduce a new survival-adjusted test procedure that makes use of both the CA trend test and the isotonic regression-based trend test. Using a broad range of experimental conditions typical of National Toxicology Program (NTP) bioassays, we conducted extensive computer simulations to compare the false-positive error rate and power of the proposed procedure with the survival-adjusted CA trend test. The new procedure competes well with the survival-adjusted CA trend test when observed tumor rates are linear in dose and performs substantially better when observed tumor rates are nonlinear in dose. Further, the proposed trend test almost always has a smaller false-positive rate than does the survival-adjusted CA trend test. We also developed an order-restricted inference-based procedure for performing multiple pairwise comparisons between each of the dose groups and the control group. The trend test and the multiple pairwise comparisons test are demonstrated using an example from a study conducted by the NTP

    Wintgen inequalities on Legendrian submanifolds of generalized Sasakian-space-forms

    Get PDF
    summary:A submanifold MmM^m of a generalized Sasakian-space-form M2n+1(f1,f2,f3)\overline{M}^{2n+1}(f_1,\allowbreak f_2,f_3) is said to be CC-totally real submanifold if ξΓ(TM)\xi\in \Gamma(T^\bot M) and ϕXΓ(TM)\phi X\in \Gamma(T^\bot M) for all XΓ(TM)X\in \Gamma(TM). In particular, if m=nm=n, then MnM^n is called Legendrian submanifold. Here, we derive Wintgen inequalities on Legendrian submanifolds of generalized Sasakian-space-forms with respect to different connections; namely, quarter symmetric metric connection, Schouten-van Kampen connection and Tanaka-Webster connection

    Development of Optical Parametric Oscillator Tunable in the Range 970-1460 nm

    Get PDF
    Optical parametric oscillator (OPO) tunable in the range 970-1460 nm has been developed using bet barium borate (BBO) crystal as the gain medium and second harmonic of Nd:YAG laser as pump source. Two sets of resonators were used to cover the range; first was nearly degenerate (970-1180 nm) and the second was nondegenerate (1240-1460 nm). The measured threshold pump pulse energy was nearly 8 mJ. Maximum signal pulse energy of about 14 mJ was obtained for pump pulse energy of nearly 31 mJ. Power scaling efficiency was about 70 per cent. The signal pulse width was ~5 ns corresponding to the pump pulse width of ~ 9 ns. OPO signal beam quality was Gaussian although the pump beam was top-hat multimode.Defence Science Journal, 2011, 61(4), pp.377-382, DOI:http://dx.doi.org/10.14429/dsj.61.56

    Evaluation of immunization coverage among children aged 12-23 months in Surendranagar city

    Get PDF
    Background: Infectious diseases are a major cause of morbidity & mortality in children. One of the most cost effective & easy methods for child survival is immunization. In May 1974, the World Health Organization (WHO) officially launched a global immunization programme known as Expanded Programme of immunization (EPI) to protect all the children of the world against 6 Vaccine Preventable Diseases by the year 2000. It was later redesignated as Universal Immunization Programme (UIP) since 1985. The objectives of this study were to assess the dropout rate and primary immunization coverage of children aged 12-23 months in Surendranagar city and to know the various reasons for partially or not immunizing the child.Methods: A community-based cross-sectional study. Thirty clusters were selected out of a total of 282 blocks of Surendranagar using the cluster sampling method. Cluster sampling method was used for sample selection and the proforma designed by UNICEF was used as a study tool. Sample size was 210 children (7 Children from each cluster) of aged 12-23 months. The obtained data were analyzed using appropriate statistical tests like Z test and X2 test. Results: Out Of the 210 surveyed children, 121(57.62%) were males and 89(42.38%) were females. Immunization card was available for 69.52% of children and fully immunized were 70.47%. Coverage was highest for BCG (95.71%) followed by OPV3 (82.85%), DPT3 (79.52%) and lowest for measles (75.23%). As far as the dropout rate is concerned, it was 21.39%, 10.21%, and 9.37% for BCG to measles, DPT1 to DPT3, and OPV1 to OPV3, respectively. Amongst the various reasons main reasons for dropout or unimmunization of children were ignorance in about 64% and lack of information regarding time, place and schedule (21%).Conclusions: Improvement should focus on reducing the dropout rate from DPT2/OPV2 to DPT3/OPV3 and improving coverage of measles and also Vitamin A

    CDR1, a multidrug resistance gene from Candida albicans, contains multiple regulatory domains in its promoter and the distal AP-1 element mediates its induction by miconazole

    Get PDF
    We previously demonstrated that the CDR1 gene, encoding a multidrug transporter in Candida albicans, is differentially upregulated by various drugs and steroids. In order to get an insight into the molecular basis of the induction of this gene we analyzed its promoter region. The transcription start site was mapped to 63 nucleotides upstream of the initiating ATG. Reporter assays revealed the presence of four upstream activating and four upstream repressing sequence domains along the entire promoter. Like the native gene, promoter-luciferase recombinants showed enhanced activity in response to various stresses like drugs, human steroid hormones and heavy metals. Mutational analysis demonstrated that while the proximal promoter (−345/+1) contains all the regulatory domains required for its induction by various other stresses, the miconazole response is mediated via the distal promoter (−857/−1147), harboring an AP-1 site. The involvement of the AP-1 element in mediating the latter effect was evident by an increase in AP-1 binding activity following miconazole treatment

    Diffraction of an Off-axis Vector-Beam by a Tilted Aperture

    Full text link
    Manifestations of orbital angular momentum induced effects in the diffraction of a radially polarized vector beam by an off-axis tilted aperture are studied both experimentally and theoretically. Experiments were carried out to extract the degree of circular polarization, which was shown to be proportional to the on-axis component of the spin angular momentum density. We report a clear separation of the regions of dominance of the right and left circular polarizations associated with positive and negative topological charges respectively, which is reminiscent of the standard vortex-induced transverse shift, albeit in the diffraction scenario. The experimental results are supported by model simulations and the agreement is quite satisfactory. The results are useful to appreciate the orbit-orbit related effects due to unavoidable misalignment problems (especially for vortex beams)
    corecore