98,095 research outputs found
Transverse Momentum Distribution and Elliptic Flow of Charged Hadrons in + collisions at GeV using HYDJET++
Recent experimental observations of the charged hadron properties in
collisions at GeV contradict many of the theoretical models of particle
production including two-component Monte Carlo Glauber model. The experimental
results show a small correlation between the charged hadron properties and the
initial geometrical configurations (e.g. body-body, tip-tip etc.) of
collisions. In this article, we have modified the Monte Carlo HYDJET++ model to
study the charged hadron production in collisions at GeV
center-of-mass energy in tip-tip and body-body initial configurations. We have
modified the hard as well as soft production processes to make this model
suitable for collisions. We have calculated the pseudorapidity
distribution, transverse momentum distribution and elliptic flow distribution
of charged hadrons with different control parameters in various geometrical
configurations possible for collision. We find that HYDJET++ model
supports a small correlation between the various properties of charged hadrons
and the initial geometrical configurations of collision. Further, the
results obtained in modified HYDJET++ model regarding and
elliptic flow () suitably matches with the experimental data of
collisions in minimum bias configuration.Comment: 29 pages, 25 figures. Accepted for Publication in EPJ
On the relationship between the modifications to the Raychaudhuri equation and the canonical Hamiltonian structures
The problem of obtaining canonical Hamiltonian structures from the equations
of motion, without any knowledge of the action, is studied in the context of
the spatially flat Friedmann-Robertson-Walker models. Modifications to
Raychaudhuri equation are implemented independently as quadratic and cubic
terms of energy density without introducing additional degrees of freedom.
Depending on their sign, modifications make gravity repulsive above a curvature
scale for matter satisfying strong energy condition, or more attractive than in
the classical theory. Canonical structure of the modified theories is
determined demanding that the total Hamiltonian be a linear combination of
gravity and matter Hamiltonians. In the quadratic repulsive case, the modified
canonical phase space of gravity is a polymerized phase space with canonical
momentum as inverse trigonometric function of Hubble rate; the canonical
Hamiltonian can be identified with the effective Hamiltonian in loop quantum
cosmology. The repulsive cubic modification results in a `generalized
polymerized' canonical phase space. Both of the repulsive modifications are
found to yield singularity avoidance. In contrast, the quadratic and cubic
attractive modifications result in a canonical phase space in which canonical
momentum is non-trigonometric and singularities persist. Our results hint on
connections between repulsive/attractive nature of modifications to gravity
arising from gravitational sector and polymerized/non-polymerized gravitational
phase space.Comment: 22 pages with two new plots. Discussion on uniqueness added, and
possible links with existing models expanded. Periodicity for 'generalized
polymerized' theory and its comparison with standard polymerization
discussed. References added. To appear in CQ
Dual automorphism-invariant modules
A module is called an automorphism-invariant module if every isomorphism
between two essential submodules of extends to an automorphism of . This
paper introduces the notion of dual of such modules. We call a module to be
a dual automorphism-invariant module if whenever and are small
submodules of , then any epimorphism with
small kernel lifts to an endomorphism of . In this paper we give
various examples of dual automorphism-invariant module and study its
properties. In particular, we study abelian groups and prove that dual
automorphism-invariant abelian groups must be reduced. It is shown that over a
right perfect ring , a lifting right -module is dual
automorphism-invariant if and only if is quasi-projective.Comment: To appear in Journal of Algebr
Impact of Organic Farming on Yield and Quality of BASMATI Rice and Soil Properties
The management of soil organic matter is critical to maintain a productive organic farming system. No one source of nutrient usually suffices to maintain productivity and quality control in organic system. In addition, the inputs to supplement nutrient avail-ability are often not uniform presenting additional challenges in meeting the nutrient requirement of crops in organic systems. With this concept, a field experiment was conducted at the research farm of Indian Agricultural Research Institute, New Delhi, India during 2003-06 in rice-wheat-green gram cropping system. In this experiment, different treatments comprising organic amendments such as Blue Green Algae (BGA) 15kg/ha, Azolla 1.0 tonne/ha, Vermicompost and Farm Yard Manure (FYM) 5.0 tonne/ha each applied alone or in combination were tested in organic crop production. These treatments were compared with absolute control (N0P0K0) and recommended dose of chemical fertilizer (N80P40K40). In wheat crop Azotobacter replaced Azolla, but other treatments remained same. For rice, a scented variety ‘Pusa Basmati 1’ and for wheat and green gram HYVs were taken. Biomass of green gram was incorporated in soil after picking of pods and wheat was sown using zero tillage practice. The obser-vations on grain yield, contents of Fe, Zn, Mn and Cu in rice grains, insect pest inci-dence, soil nutrients and microbial activity were taken.
Results revealed a significant enhancement in grain yield of rice over absolute control due to the application of different organic amendments applied alone or in combina-tions. Rice grain yield increased by 114 to 116.8% over absolute control when all the 4 organic amendments were applied altogether. The rice grain yield (4.0 t ha-1) obtained under combined application of four organic amendments was at par with the yield recorded under recommended dose of chemical fertilizer application. An interesting observation recorded was that there was no serious attack of any insect pest or dis-ease in organically grown crop. Soil microbial population (Actinomycetes, Bacteria, Fungi and BGA) enhanced due to the application of organic amendments in compari-son to absolute control as well as recommended fertilizer application that in turn re-sulted in a notable enhancement in soil dehydrogenase and phosphatase enzyme activity. Soil organic carbon and available phosphorus contents were also found to be significantly increased due to organic farming practice over control as well as chemical fertilizer application.
Rice grain analysis for nutrients viz. Fe, Zn, Mn and Cu showed a significant increase in Fe and Mn content in the treatments having 2 or more organic amendments over control. Zn and Cu content also increased but the increment was significant with combined application of 3 or 4 organic amendments.
The study revealed that addition of four organic amendments viz. BGA, Azolla, FYM and Vermicompost could give the optimum yield (4.05 t/ha) of organic Basmati rice and improve grain and soil quality
- …