1,833 research outputs found

    Geometry fluctuations in a two-dimensional quantum antiferromagnet

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    The paper considers the effects of random fluctuations of the local spin connectivities (fluctuations of the geometry) on ground state properties of a two-dimensional quantum antiferromagnet. We analyse the behavior of spins described by the Heisenberg model as a function of what we call phason flip disorder, following a terminology used for aperiodic systems. The calculations were carried out both within linear spin wave theory and using quantum Monte Carlo simulations. An "order by disorder" phenomenon is observed in this model, wherein antiferromagnetism is found to be enhanced by phason disorder. The value of the staggered order parameter increases with the number of defects, accompanied by an increase in the ground state energy of the system.Comment: 5 pages, 7 figures. Shortened and corrected version (as accepted for publication in Physical Review B

    A phason disordered two dimensional quantum antiferromagnet

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    We examine a novel type of disorder in quantum antiferromagnets. Our model consists of localized spins with antiferromagnetic exchanges on a bipartite quasiperiodic structure, which is geometrically disordered in such a way that no frustration is introduced. In the limit of zero disorder, the structure is the perfect Penrose rhombus tiling. This tiling is progressively disordered by augmenting the number of random "phason flips" or local tile-reshuffling operations. The ground state remains N\'eel ordered, and we have studied its properties as a function of increasing disorder using linear spin wave theory and quantum Monte Carlo. We find that the ground state energy decreases, indicating enhanced quantum fluctuations with increasing disorder. The magnon spectrum is progressively smoothed, and the effective spin wave velocity of low energy magnons increases with disorder. For large disorder, the ground state energy as well as the average staggered magnetization tend towards limiting values characteristic of this type of randomized tilings.Comment: 5 pages, 7 figure

    Neutrosophic Fuzzy Hierarchical Clustering for Dengue Analysis in Sri Lanka

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    Estimation of combining ability for yield and yield component traits in upland rice (Oryza Sativa L.) of Uttarakhand hills

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    Combining ability for grain yield and its component characters in rainfed upland rice (Oryza sativa L.) were studied during Kharif 2014 using half diallel involving ten parents viz., VL Dhan 221, Vivek Dhan 154, VL 30240, VL 7620, VL 30560, VL 8116, VL 8549, VL 8724, VL 8732 and Sukradhan1. Both general combining ability (gca) and specific combining ability (sca) variances were found to be highly significant for the characters viz., plant height (gca=85.42; sca=23.12), days to 50% flowering (gca=101.61; sca=42.61), days to maturity (gca=90.37; sca=37.73), tillers per plant (gca=4.63; sca=1.38), panicle per plant (gca=2.36; sca=0.90),kernel length (gca=28.88; sca=23.61), kernel width (gca=1.64; sca=1.92),1000 grain weight (gca=3.60; sca=4.91), grain yield per plot (gca=8.57; sca=3.03), fertile grains per panicle (gca=690.67; sca=300.95) and grains per panicle (gca=1050.58; sca=437.75) indicating the importance of additive and non-additive gene actions in the expression of these traits. However, predominance of non-additive gene action was recorded for all the characters. Parents VL Dhan 221, VL 7620, VL 30560, Sukradhan 1 were good general combiners for grain yield and related characters. VL Dhan 221 and Vivek Dhan 154 were good general combiners for plant height and earliness. On the basis of specific combining ability effects, cross combinations Vivek Dhan 154 x VL 8549, VL 7620 x VL 30560, VL 8549 x VL 8732, VL 30560 x VL 8116 and VL 30240 x VL 8116 were the best specific combiner for grain yield per plot and other associated characters viz., plant height, days to 50% flowering, days to maturity, kernel length and kernal width

    A Novel Method for Optimal Solution of Fuzzy Chance Constraint Single-Period Inventory Model

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    A method is proposed for solving single-period inventory fuzzy probabilistic model (SPIFPM) with fuzzy demand and fuzzy storage space under a chance constraint. Our objective is to maximize the total profit for both overstock and understock situations, where the demand D~j for each product j in the objective function is considered as a fuzzy random variable (FRV) and with the available storage space area W~, which is also a FRV under normal distribution and exponential distribution. Initially we used the weighted sum method to consider both overstock and understock situations. Then the fuzziness of the model is removed by ranking function method and the randomness of the model is removed by chance constrained programming problem, which is a deterministic nonlinear programming problem (NLPP) model. Finally this NLPP is solved by using LINGO software. To validate and to demonstrate the results of the proposed model, numerical examples are given

    Prevalence of uterine lesions associated with leiomyomas and role of endometrial biopsy in management

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    Background: Present study highlights association between symptomatic patients of fibroids and its coexistence with pathologies like endometriosis, adenomyosis, polyp, endometrial hyperplasia and carcinoma. The aim was evaluating role of endometrial biopsy before surgery.Methods: The study was observational cohort, conducted on women operated for fibroid or recently diagnosed with fibroid. 150 women were included. Histopathology reports of already operated were analysed for association between uterine pathology and fibroid. In prospective cases ultrasonography findings was noted and patients having leiomyoma underwent biopsy and reports studied for association. Chi-square test done to find association between qualitative variable and p value <0.05 considered significant.Results: Out of 150, 24.6% had adenomyosis, 14% had endometrial hyperplasia in which 2% had atypia and 12% without atypia, 8.6% had cervical polyp, 5.33% had endometrial polyp, 4% had endometriosis while 42.7% had no association.Conclusions: This study revealed increasing trend of coexistence of leiomyomas with uterine pathologies. Early identification of endometrial pathologies on clinical history and imaging helps in selection of high-risk patients who need biopsy to rule out malignancy thus avoiding routine D and C which is done for every case

    Normalizing of estrous cycle in polycystic ovary syndrome (PCOS) induced rats with Tephrosia purpurea (Linn.) Pers.

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    This study evaluates the potentiality of an herbal plant Tephrosia purpurea (Linn.) Pers. in the treatment of Letrozole induced polycystic ovary syndrome (PCOS) using female Albino wistar rats. Seed powder of T. purpurea at concentration of 200 mg/kg body weight with milk as a carrier vehicle 3ml/kg body weight, given for at least 3 consecutive estrous cycles. Vaginal smear, FSH, LH, Testosterone, and Estrogen were analyzed to determine the fluctuations in sex steroid level in PCOS induced rats. The plasma testosterone and estrogen levelwere found to be significantly increased in rats with PCOS whereas Follicle stimulating hormone and Leutinizing hormone did not show any changes. When compared with control the PCOS induced rats showed characteristic ovary with high incidence of ovarian cyst. All the parameters assessed were significantly improved after the treatment with T. purpurea and achieved level close to 80% normalcy. Effect of T. purpurea significantly reduced histopathological changes in ovary and endocrinological and biochemical changes induced by hyperandrogenism. Further to check ovulation and fertility female rats were mated and pregnancy was confirmed. Thus potential of T. purpurea in the treatment of PCOS using an animal model suggested being a good alternative therapy in the treatment of PCOS
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