3,304 research outputs found
Active elastic dimers: self-propulsion and current reversal on a featureless track
We present a Brownian inchworm model of a self-propelled elastic dimer in the
absence of an external potential. Nonequilibrium noise together with a
stretch-dependent damping form the propulsion mechanism. Our model connects
three key nonequilibrium features -- position-velocity correlations, a nonzero
mean internal force, and a drift velocity. Our analytical results, including
striking current reversals, compare very well with numerical simulations. The
model unifies the propulsion mechanisms of DNA helicases, polar rods on a
vibrated surface, crawling keratocytes and Myosin VI. We suggest experimental
realizations and tests of the model.Comment: 4 page
Elastic constants from microscopic strain fluctuations
Fluctuations of the instantaneous local Lagrangian strain
, measured with respect to a static ``reference''
lattice, are used to obtain accurate estimates of the elastic constants of
model solids from atomistic computer simulations. The measured strains are
systematically coarse- grained by averaging them within subsystems (of size
) of a system (of total size ) in the canonical ensemble. Using a
simple finite size scaling theory we predict the behaviour of the fluctuations
as a function of and extract elastic
constants of the system {\em in the thermodynamic limit} at nonzero
temperature. Our method is simple to implement, efficient and general enough to
be able to handle a wide class of model systems including those with singular
potentials without any essential modification. We illustrate the technique by
computing isothermal elastic constants of the ``soft'' and the hard disk
triangular solids in two dimensions from molecular dynamics and Monte Carlo
simulations. We compare our results with those from earlier simulations and
density functional theory.Comment: 24 pages REVTEX, 10 .ps figures, version accepted for publication in
Physical Review
Farm-economics of genetically improved carp strains in major Asian countries and carp seed price policy model
The study has conducted the micro level analysis of hatchery operators, fishseed-rearing farmers and carp farmers with respect to their socio-economic characteristics, infrastructural development, husbandry practices and economics returns, based on the survey and on-farm trial data collected by the research partners in six Asian countries, viz. Bangladesh, China, India, Indonesia, Thailand and Vietnam. The genetically-improved carp strain is economically viable and socially acceptable. The attractive profits to hatchery operators and nursery and carp farmers have created conducive environment for the dissemination of improved carp strain. Price policy models for improved strains have been developed. The premium price for fingerlings and broodstock with improved strain has been assessed. The high price of genetically-improved nuclear seed and broodstock would build self-supportive research and extension systems in the country. A business plan for Jayanti rohu has been worked out, as an example for replacement of rohu by Jayanti rohu.Livestock Production/Industries,
Study of dynamical charge fluctuations in the hadronic medium
The dynamical charge fluctuations have been studied in ultra-relativistic
heavy-ion collisions by using hadronic model simulations, such as UrQMD and
HIJING. The evolution of fluctuations has been calculated at different time
steps during the collision as well as different observation window in
pseudorapidity (\DelEta). The final state effects on the fluctuations have been
investigated by varying ~ and the time steps with the aim
of obtaining an optimum observation window for capturing maximum fluctuations.
It is found that ~ between 2.0 and 3.5 gives the best
coverage for the fluctuations studies. The results of these model calculations
for Au+Au collisions at ~=~7.7 to 200~GeV and for Pb+Pb
collisions at 2.76 TeV are presented and compared with available experimental
data from the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron
Collider (LHC).Comment: 6 pages, 4 Figure
Primjene teorije grafova: topologijski modeli za predvi|anje CDK-1 inhibicijske aktivnosti aloizina
Relationship between the topological indices and cyclin-dependent kinase-1 (CDK-1/cyclin B) inhibitory activity of 6-phenyl[5H]pyrrolo[2,3-b]pyrazines (aloisines) was investigated. Three topological indices – the Wiener Index, a distance-based topological descriptor, the Zagreb group parameter, an adjacency based topological descriptor, and the eccentric connectivity index, an adjacency-cum-distance based topological descriptor were used in the study. A data set comprising 51 analogues of aloisine was selected for the present study. Values of the Wiener index, the Zagreb group parameter and the eccentric connectivity index for each of the 51 analogues included in the data set were computed using an in-house computer program. Resultant data was analyzed and suitable models were developed after identification of active ranges. A biological activity was then assigned to each compound using these models, which was then compared with the reported CDK-1 inhibitory activity. Accuracy of prediction using these models was found to vary from a minimum of ≈82 % to a maximum of 84 %. .Istraživan je odnos izmđ|u topologijskih indeksa i CDK-1 inhibicijske aktivnosti 5-fenil[5H]pirolo[2,3-b]- pirazina (aloizina). Upotrebljena su tri topologijska indeksa: Wienerov indeks, zagrebački indeks i ekscentrični indeks povezanosti, koji su izračunani za 51 aloizin. Dobiveni modeli predviđaju inhibijsku aktivnosti aloizina s točnošću od 82–84 %
Primjene teorije grafova: topologijski modeli za predvi|anje CDK-1 inhibicijske aktivnosti aloizina
Relationship between the topological indices and cyclin-dependent kinase-1 (CDK-1/cyclin B) inhibitory activity of 6-phenyl[5H]pyrrolo[2,3-b]pyrazines (aloisines) was investigated. Three topological indices – the Wiener Index, a distance-based topological descriptor, the Zagreb group parameter, an adjacency based topological descriptor, and the eccentric connectivity index, an adjacency-cum-distance based topological descriptor were used in the study. A data set comprising 51 analogues of aloisine was selected for the present study. Values of the Wiener index, the Zagreb group parameter and the eccentric connectivity index for each of the 51 analogues included in the data set were computed using an in-house computer program. Resultant data was analyzed and suitable models were developed after identification of active ranges. A biological activity was then assigned to each compound using these models, which was then compared with the reported CDK-1 inhibitory activity. Accuracy of prediction using these models was found to vary from a minimum of ≈82 % to a maximum of 84 %. .Istraživan je odnos izmđ|u topologijskih indeksa i CDK-1 inhibicijske aktivnosti 5-fenil[5H]pirolo[2,3-b]- pirazina (aloizina). Upotrebljena su tri topologijska indeksa: Wienerov indeks, zagrebački indeks i ekscentrični indeks povezanosti, koji su izračunani za 51 aloizin. Dobiveni modeli predviđaju inhibijsku aktivnosti aloizina s točnošću od 82–84 %
Yellow-bellied marmot population dynamics: demographic mechanisms of growth and decline
This is the publisher's version, also available electronically from http://www.esajournals.org/doi/abs/10.1890/03-0513Multiple environmental factors may act synergistically to influence demographic characteristics, and ultimately the dynamics, of biological populations. Using prospective and retrospective analyses of demographic data from a 40-year study of individually marked animals, we investigated the demographic mechanisms of the temporal and spatial dynamics of a yellow-bellied marmot (Marmota flaviventris) population. Prospective elasticity analyses indicated juvenile survival (Pj) would have the largest relative influence on the projected population growth rate (λ). Relative magnitudes of elasticities did not differ between years characterized by positive (λ > 1.0) and negative (λ < 1.0) population growth. However, retrospective analyses of a life table response experiment (LTRE) revealed that changes in fertility (F), followed by age of first reproduction (α) made the largest contributions to observed annual changes in λ. Changes in F and α made the largest contributions to annual declines in λ, whereas changes in Pj also were important to cause increases in λ. Population dynamic differences among marmot colonies were due primarily to spatial variations in α and Pj. Our results indicate that changes in reproductive parameters (α and F) primarily drive the temporal dynamics of our study population, and that demographic mechanisms of population increases might differ from those of population declines. Studies of the regulation of yellow-bellied marmot populations should focus on the factors or processes influencing reproductive parameter
Effect of various trace elements on the growth and sporulation of Claviceps Microcephala and Microxyphiella hibiscifolia
Out of fifteen trace elements tested, Fe, Zn, Mn and Cu were found to be essential for the growth as well as sporulation of Claviceps microcephala and Microxyphiella hibiscifolia; Mo for C. microcephala but not for M. hibiscifolia; Ca for M. hibiscifolia but not for C. microcephala. No other trace element was found to be essential for either of these fungi. Optimum concentrations in ppm of essential trace elements were found to be as follows: C. microcephala, Fe 0.2, Zn 0.1, Mn 1.0, Cu 0.01 (0.01-0.1) and Mo 1.0; M. hibiscifolia, Fe 0.01 (0.01-0.1), Zn 10.0, Mn 1.0, Cu 10.0 and Ca 10.0. Concentrations higher than the optimum were progressively inhibitory to the respective fungi
THE DYNAMICS OF RAPE IN MODERN INDIAN SOCIETY
Rape is malum in se. In modern India the institution of rape has flourishedimmensely in recent times, and presently it is a national problem. It is a challenge to thecontemporary thinking. Gender equality is enshrined in the Indian constitution. In ancienttimes rape existed in Europe while women in India had divine personification as Shakti andin modern times millions of Indians visit Shakti temples with liberal offerings.This paper addresses dynamics of rape with particular reference to India. Rape is amultidimensional and dynamic phenomenon. Its perception may vary from radical to liberal,and the legal definition keeps evolving. Mathematically it may be modeled as a space-timefunction. In 2013 the definition of rape was revised both in India and US. It, however,differs. The paper examines recently introduced Indian law to reduce rape incidents.There are various areas which need attention to have insight into the phenomenon ofrape and measures to control the incidents. This includes understanding the effect of socioeconomic-demographic predictor variables in reduction of the incidents. The authors haveapplied statistical analysis using correlation to rape data from all the 35 regions of Indiawith eleven socio-economic-demographic predictor variables to find the effect of thevariables on incidents of rape. It was found that only literacy status, or literacy status as aproxy, for male and female in urban population indicated significant desirable effect on thenumber of rape incidents. This sets a direction for further research. The rape challenge shouldbe addressed with afresh look from multidisciplinary perspective besides law andenforcement. The fusion of data, analyses, and ideas including from sociological, cultural,psychological, and religious aspects, and encouraging merging of tools from disciplines,should provide an insightful and sound approach to find solution to the intractable socialproblem. Also social change with the universal wisdom thoughts of great minds like MahatmaGandhi and Elie Wiesel is desirable to eliminate ills, including rape, from the modern society
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