1,213 research outputs found

    Renormalization group maps for Ising models in lattice gas variables

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    Real space renormalization group maps, e.g., the majority rule transformation, map Ising type models to Ising type models on a coarser lattice. We show that each coefficient of the renormalized Hamiltonian in the lattice gas variables depends on only a finite number of values of the renormalized Hamiltonian. We introduce a method which computes the values of the renormalized Hamiltonian with high accuracy and so computes the coefficients in the lattice gas variables with high accuracy. For the critical nearest neighbor Ising model on the square lattice with the majority rule transformation, we compute over 1,000 different coefficients in the lattice gas variable representation of the renormalized Hamiltonian and study the decay of these coefficients. We find that they decay exponentially in some sense but with a slow decay rate. We also show that the coefficients in the spin variables are sensitive to the truncation method used to compute them.Comment: 22 pages, 9 color postscript figures; minor revisions in version

    Goodness-of-Fit Tests to study the Gaussianity of the MAXIMA data

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    Goodness-of-Fit tests, including Smooth ones, are introduced and applied to detect non-Gaussianity in Cosmic Microwave Background simulations. We study the power of three different tests: the Shapiro-Francia test (1972), the uncategorised smooth test developed by Rayner and Best(1990) and the Neyman's Smooth Goodness-of-fit test for composite hypotheses (Thomas and Pierce 1979). The Smooth Goodness-of-Fit tests are designed to be sensitive to the presence of ``smooth'' deviations from a given distribution. We study the power of these tests based on the discrimination between Gaussian and non-Gaussian simulations. Non-Gaussian cases are simulated using the Edgeworth expansion and assuming pixel-to-pixel independence. Results show these tests behave similarly and are more powerful than tests directly based on cumulants of order 3, 4, 5 and 6. We have applied these tests to the released MAXIMA data. The applied tests are built to be powerful against detecting deviations from univariate Gaussianity. The Cholesky matrix corresponding to signal (based on an assumed cosmological model) plus noise is used to decorrelate the observations previous to the analysis. Results indicate that the MAXIMA data are compatible with Gaussianity.Comment: MNRAS, in pres

    Follow-up household survey in Agra District

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    This follow-up household survey in Agra District, India, was conducted with funding from USAID under the Population Council’s Asia and Near East Operations Research and Technical Assistance (ANE OR/TA) Project. The main objective of this study, as noted in this report, is to assess changes in the program indicators of family welfare activities, including some of the selected reproductive health indicators, from 1995 (before method-specific targets were withdrawn) and 1997 (30 months after targets were withdrawn). The study’s objectives are to detect changes in FP knowledge and use among currently married women in rural areas; detect changes in level of unmet need for spacing and limiting births; detect changes in use of health services by pregnant and postpartum women; identify the differential use of FP methods, antenatal and postnatal services, child immunization, and other reproductive health services; assess reproductive tract infections among ever-married women in rural areas as reported by them; and assess the level of unwanted pregnancies, incidence of abortions, and post-abortion services

    The extended empirical process test for non-Gaussianity in the CMB, with an application to non-Gaussian inflationary models

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    In (Hansen et al. 2002) we presented a new approach for measuring non-Gaussianity of the Cosmic Microwave Background (CMB) anisotropy pattern, based on the multivariate empirical distribution function of the spherical harmonics a_lm of a CMB map. The present paper builds upon the same ideas and proposes several improvements and extensions. More precisely, we exploit the additional information on the random phases of the a_lm to provide further tests based on the empirical distribution function. Also we take advantage of the effect of rotations in improving the power of our procedures. The suggested tests are implemented on physically motivated models of non-Gaussian fields; Monte-Carlo simulations suggest that this approach may be very promising in the analysis of non-Gaussianity generated by non-standard models of inflation. We address also some experimentally meaningful situations, such as the presence of instrumental noise and a galactic cut in the map.Comment: 15 pages, 6 figures, submitted to Phys. Rev.

    Breeding Drought-Tolerant Pearl Millet using conventional and genomic approaches: Achievements and prospects

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    Pearl millet [Pennisetum glaucum (L.) R. Br.] is a C4 crop cultivated for its grain and stover in crop-livestock-based rain-fed farming systems of tropics and subtropics in the Indian subcontinent and sub-Saharan Africa. The intensity of drought is predicted to further exacerbate because of looming climate change, necessitating greater focus on pearl millet breeding for drought tolerance. The nature of drought in different target populations of pearl millet-growing environments (TPEs) is highly variable in its timing, intensity, and duration. Pearl millet response to drought in various growth stages has been studied comprehensively. Dissection of drought tolerance physiology and phenology has helped in understanding the yield formation process under drought conditions. The overall understanding of TPEs and differential sensitivity of various growth stages to water stress helped to identify target traits for manipulation through breeding for drought tolerance. Recent advancement in high-throughput phenotyping platforms has made it more realistic to screen large populations/germplasm for drought-adaptive traits. The role of adapted germplasm has been emphasized for drought breeding, as the measured performance under drought stress is largely an outcome of adaptation to stress environments. Hybridization of adapted landraces with selected elite genetic material has been stated to amalgamate adaptation and productivity. Substantial progress has been made in the development of genomic resources that have been used to explore genetic diversity, linkage mapping (QTLs), marker-trait association (MTA), and genomic selection (GS) in pearl millet. High-throughput genotyping (HTPG) platforms are now available at a low cost, offering enormous opportunities to apply markers assisted selection (MAS) in conventional breeding programs targeting drought tolerance. Next-generation sequencing (NGS) technology, micro-environmental modeling, and pearl millet whole genome re-sequence information covering circa 1,000 wild and cultivated accessions have helped to greater understand germplasm, genomes, candidate genes, and markers. Their application in molecular breeding would lead to the development of high-yielding and drought-tolerant pearl millet cultivars. This review examines how the strategic use of genetic resources, modern genomics, molecular biology, and shuttle breeding can further enhance the development and delivery of drought-tolerant cultivars

    Observations from a study tour of Bangladesh and Indonesia on their family welfare programme

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    Bangladesh has a successful family planning (FP) program and has succeeded in bringing about a demographic transition at a much faster rate than many of its neighboring countries. The contraceptive prevalence rate in Bangladesh increased from 3 percent in 1971 to 45 percent in 1993, and the fertility rate decreased from 7.0 to 3.4 births per woman during the same period. This reflects the effort that the Government of Bangladesh, with the help of international agencies, has made to educate couples about FP and increase access and choice of contraceptive methods, even in remote areas. Another predominantly Muslim country that has achieved remarkable success in FP is Indonesia which has had unprecedented economic growth in recent years. A visit to these countries to study their FP programs provided opportunities to closely observe activities that have contributed to this success. The Population Council, under the Asia and Near East Operations Research and Technical Assistance (ANE OR/TA) project funded by USAID, organized a study tour of Bangladesh and Indonesia for Indian officials, and results are provided in this report

    Follow-up household survey in Sitapur District

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    This follow-up household survey in Sitapur, India, was conducted with funding from USAID under the Population Council\u27s Asia and Near East Operations Research and Technical Assistance (ANE OR/TA) Project. The main objective of the study, as noted in this report, is to assess changes in the program indicators of family welfare activities, including some of the selected reproductive health indicators, from 1994–95 (before the method-specific targets were withdrawn) and 1997 (30 months after the targets were withdrawn). The study has the following immediate objectives: detect changes in family planning (FP) knowledge and use among currently married women in rural areas; detect changes in level of unmet need for spacing and limiting births; detect changes in use of health services by pregnant and postpartum women; identify the differential use of FP methods, antenatal and postnatal services, child immunization, and other reproductive health services; assess reproductive tract infections among ever-married women in rural areas; and assess the level of unwanted pregnancies, incidence of abortions, and post-abortion services

    Pseudo-unitary symmetry and the Gaussian pseudo-unitary ensemble of random matrices

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    Employing the currently discussed notion of pseudo-Hermiticity, we define a pseudo-unitary group. Further, we develop a random matrix theory which is invariant under such a group and call this ensemble of pseudo-Hermitian random matrices as the pseudo-unitary ensemble. We obtain exact results for the nearest-neighbour level spacing distribution for (2 X 2) PT-symmetric Hamiltonian matrices which has a novel form, s log (1/s) near zero spacing. This shows a level repulsion in marked distinction with an algebraic form in the Wigner surmise. We believe that this paves way for a description of varied phenomena in two-dimensional statistical mechanics, quantum chromodynamics, and so on.Comment: 9 pages, 2 figures, LaTeX, submitted to the Physical Review Letters on August 20, 200
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