1,608 research outputs found
A phason disordered two dimensional quantum antiferromagnet
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
Stagnating trends in complementary feeding practices in Bangladesh: An analysis of national surveys from 2004-2014.
Bangladesh has experienced steady socio-economic development. However, improvements in child growth have not kept pace. It is important to document complementary feeding (CF) practices-a key determinant of children's growth-and their trends over time. The study aims to examine trends in CF practices in children aged 6-23Â months using data from Bangladesh Demographic and Health Surveys conducted in 2004, 2007, 2011, and 2014. Multilevel logistic regression models were applied to identify independent predictors of four CF practice indicators among children 6-23Â months, namely, timely introduction of complementary foods, minimum meal frequency, minimum dietary diversity, and minimum acceptable diet. Introduction of complementary foods was achieved among 64-71% of children between 2004 and 2014. The proportion meeting minimum meal frequency increased from 2004 to 2007 (71-81%) and declined and held steady at 65% from 2011 to 2014. The proportion meeting minimum dietary diversity in 2011 and 2014 was low (25% and 28%), and so was minimum acceptable diet (19% and 20%). From 2007 to 2014, child dietary diversity decreased and the most decline was in the consumption of legumes and nuts (29% to 8%), vitamin A-rich fruits and vegetables (54% to 41%), and other fruits and vegetables (47% to 20%). Young child age (6-11Â months), poor parental education, household poverty, and residence in the Chittagong and Sylhet independently predicted poorer feeding practices. Dietary diversity and overall diet in Bangladeshi children are strikingly poor. Stagnation or worsening of feeding practices in the past decade are concerning and call for decisive policy and programme action to address inappropriate child feeding practices
Estimation of combining ability for yield and yield component traits in upland rice (Oryza Sativa L.) of Uttarakhand hills
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
Soft-collinear effects in prompt photon production
We extend next-to-leading logarithmic threshold and joint resummation for
prompt photon production to include leading collinear effects. The impact of
these effects is assessed for both fixed-target and collider kinematics. We
find them in general to be small, but noticeable.Comment: 14 pages, 12 figures, added comment on fragmentation contribution and
one more reference. Version to appear in Phys. Rev.
Reflectivity Parameter Extraction from RADAR Images Using Back Propagation Algorithm
Pattern recognition has been acknowledged as one of the promising research areas and it has drawn the awareness among many researchers since its existence at the beginning of the nineties. Multilayer Neural networks are used in pattern Recognition and classification based on the features derived from the input patterns. The Reflectivity information extracted from the Doppler Weather Radar (DWR) image helps in identifying the convective cloud type which has a strong relation to the precipitation rate. The reflectivity information is rooted in the DWR image with the help of colors and color bar is provided to distinguish among different reflectivity information. Artificial Neural network predicts the color based on the maximum likelihood estimation problem. This paper presents a best possible backpropagation algorithm for color identification in DWR images by comparing various backpropagation algorithms such as LevenbergMarquardt, Conjugate gradient, and Resilient back propagation etc.,. Pattern recognition using Neural networks presents better results compared to standard distance measures. It is observed that Levenberg-Marquardt backpropagation algorithm yields a regression value of 99% approximately and accuracy of 98
Geometry fluctuations in a two-dimensional quantum antiferromagnet
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
FTDA: Performance Enhancement of WSN using Fuzzy based Traffic Data Analysis
In the present time in Wireless Sensor Network plays an essential role in the monitoring of different physical phenomena. Monitoring of city traffic data analysis is very important in different metro cities due to rapid increase in population. This research work proposes a model for traffic data analysis using wireless sensor network incorporated with fuzzy technique. The proposed model is tested for performance parameters such as node dead rate , data packed received. The proposed model improved the efficiency compared to existing techniques of the WSN network for traffic data collection and analysis
Pollard RHO algorithm implemented to Discrete Log with Lucas sequences
The Diffie - Hellman problem may be used securely over the multiplicative group F*p, (Z/nZ)* and the group of rational points on an elliptic curve over a finite field. These groups involve large key sizes or expensive arithmetic operations. In the paper [17] paper we considered the group of Lucas sequences and described the generalization of discrete log problem with the group of Lucas sequences and adapted the baby-step giant-step algorithm to the generalization and for the computations we gave an algorithm to fast computing methods for lucas sequences based on the idea proposed by P.J.Smith. In this paper we consider the group of Lucas sequences and implement the pollard rho algorithm to the generalization of discrete log problem to the group of Lucas sequences. For the computations we implement with fast computing algorithm
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