105 research outputs found
Biological Control of F. Oxysporum F. Sp. Lycopersici Causing Wilt of Tomato by Pseudomonas Fluorescens
Abstract- Pseudomonas fluorescens is one of the major fungal biocontrol agents found in the soil and the rhizosphere of various crop systems. Ten isolates of P.fluorescens were isolated from rhizosphere soil samples collected from various tomato-growing fields and evaluated for their efficacy in increasing seed quality variables of tomato and in inhibiting the mycelial growth of Fusarium oxysporum. Pseudomonas isolate 2 produced effective results and was selected and mass multiplied. Talc and sodium alginate formulations of mass multiplied using different agents were prepared and evaluated for
their effects against fusarium wilt under greenhouse conditions. Fresh cultures of Pf2 isolate was found to increase seedling emergence and reduce fusarium wilt disease incidence when compared to the control and the formulations
Selection of effective bio-antagonistic bacteria for biological control of tomato wilt caused by Fusarium oxysporum F. sp. lycopersici
Bacteria from the rhizoplane soil and surrounding soil of healthy and Fusarium oxysporum diseased tomato plants of district regions of Karnataka were collected. The best bacterial strains, based on their ability to control development of Fusarium oxysporum isolate, were identified as BS1, BS5 and BS18. All bacterial isolates resulted effective for the in vitro control of growth of Fusarium oxysporum, where the control mechanisms used by the bacteria do not involve the secretion of fungal cell wall hydrolytic enzymes. On the other hand, all bacteria grew well in conditions similar to those that can be found at the field level (considering pH, salinity, Fe3+ and temp.) and showed a good capacity of tomato root colonization. These results suggest that Pseudomonas fluorescens isolates studied have an excellent potential to be used as biocontrol agents of Fusarium oxysporum in tomato greenhouses at the field level
Sharp-1 regulates TGF-β signaling and skeletal muscle regeneration
10.1242/jcs.136648Journal of Cell Science1273599-608JNCS
Scaling approach to itinerant quantum critical points
Based on phase space arguments, we develop a simple approach to metallic
quantum critical points, designed to study the problem without integrating the
fermions out of the partition function. The method is applied to the
spin-fermion model of a T=0 ferromagnetic transition. Stability criteria for
the conduction and the spin fluids are derived by scaling at the tree level. We
conclude that anomalous exponents may be generated for the fermion self-energy
and the spin-spin correlation functions below , in spite of the spin fluid
being above its upper critical dimension.Comment: 3 pages, 2 figures; discussion of the phase space restriction
modified and, for illustrative purposes, restricted to the tree-level
analysis of the ferromagnetic transitio
King or royal family? Testing for species boundaries in the King Cobra, Ophiophagus hannah (Cantor, 1836), using morphology and multilocus DNA analyses
Interacting Open Wilson Lines in Noncommutative Field Theories
In noncommutative field theories, it was known that one-loop effective action
describes propagation of non-interacting open Wilson lines, obeying the flying
dipole's relation. We show that two-loop effective action describes cubic
interaction among `closed string' states created by open Wilson lines. Taking
d-dimensional noncommutative [\Phi^3] theory as the simplest setup, we compute
nonplanar contribution at low-energy and large noncommutativity limit. We find
that the contribution is expressible in a remarkably simple cubic interaction
involving scalar open Wilson lines only and nothing else. We show that the
interaction is purely geometrical and noncommutative in nature, depending only
on sizes of each open Wilson line.Comment: v1: 27 pages, Latex, 7 .eps figures v2: minor wording change +
reference adde
On the Application of the Non Linear Sigma Model to Spin Chains and Spin Ladders
We review the non linear sigma model approach (NLSM) to spin chains and spin
ladders, presenting new results. The generalization of the Haldane's map to
ladders in the Hamiltonian approach, give rise to different values of the
parameter depending on the spin S, the number of legs and
the choice of blocks needed to built up the NLSM fields. For rectangular blocks
we obtain or depending on wether , is even or
odd, while for diagonal blocks we obtain . Both
results agree modulo , and yield the same prediction, namely that even (
resp. odd) ladders are gapped (resp. gapless). For even legged ladders we show
that the spin gap collapses exponentially with and we propose a
finite size correction to the gap formula recently derived by Chakravarty using
the 2+1 NSLM, which gives a good fit of numerical results. We show the
existence of a Haldane phase in the two legged ladder using diagonal blocks and
finally we consider the phase diagram of dimerized ladders.Comment: 25 pages, Latex, 7 figures in postscript files, Proc. of the 1996 El
Escorial Summer School on "Strongly Correlated Magnetic and Superconducting
Systems". Some more references are adde
Phase diagrams of spin ladders with ferromagnetic legs
The low-temperature properties of the spin S=1/2 ladder with anisotropic
ferromagnetic legs are studied using the continuum limit bosonization approach.
The weak-coupling ground state phase diagram of the model is obtained for a
wide range of coupling constants and several unconventional gapless
''spin-liquid'' phases are shown to exist for ferromagnetic coupling. The
behavior of the ladder system in the vicinity of the ferromagnetic instability
point is discussed in detail.Comment: 11 pages, 4 figure
Edge reconstructions in fractional quantum Hall systems
Two dimensional electron systems exhibiting the fractional quantum Hall
effects are characterized by a quantized Hall conductance and a dissipationless
bulk. The transport in these systems occurs only at the edges where gapless
excitations are present. We present a {\it microscopic} calculation of the edge
states in the fractional quantum Hall systems at various filling factors using
the extended Hamiltonian theory of the fractional quantum Hall effect. We find
that at the quantum Hall edge undergoes a reconstruction as the
background potential softens, whereas quantum Hall edges at higher filling
factors, such as , are robust against reconstruction. We present
the results for the dependence of the edge states on various system parameters
such as temperature, functional form and range of electron-electron
interactions, and the confining potential. Our results have implications for
the tunneling experiments into the edge of a fractional quantum Hall system.Comment: 11 pages, 9 figures; minor typos corrected; added 2 reference
Spin Stiffness of Mesoscopic Quantum Antiferromagnets
We study the spin stiffness of a one-dimensional quantum antiferromagnet in
the whole range of system sizes and temperatures . We show that for
integer and half-odd integer spin case the stiffness differs fundamentally in
its and dependence, and that in the latter case the stiffness exhibits
a striking dependence on the parity of the number of sites. Integer spin chains
are treated in terms of the non-linear sigma model, while half-odd integer spin
chains are discussed in a renormalization group approach leading to a Luttinger
liquid with Aharonov-Bohm type boundary conditions.Comment: 12 pages, LaTe
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