171 research outputs found
Multifractal eigenstates of quantum chaos and the Thue-Morse sequence
We analyze certain eigenstates of the quantum baker's map and demonstrate,
using the Walsh-Hadamard transform, the emergence of the ubiquitous Thue-Morse
sequence, a simple sequence that is at the border between quasi-periodicity and
chaos, and hence is a good paradigm for quantum chaotic states. We show a
family of states that are also simply related to Thue-Morse sequence, and are
strongly scarred by short periodic orbits and their homoclinic excursions. We
give approximate expressions for these states and provide evidence that these
and other generic states are multifractal.Comment: Substantially modified from the original, worth a second download. To
appear in Phys. Rev. E as a Rapid Communicatio
Using the Hadamard and related transforms for simplifying the spectrum of the quantum baker's map
We rationalize the somewhat surprising efficacy of the Hadamard transform in
simplifying the eigenstates of the quantum baker's map, a paradigmatic model of
quantum chaos. This allows us to construct closely related, but new, transforms
that do significantly better, thus nearly solving for many states of the
quantum baker's map. These new transforms, which combine the standard Fourier
and Hadamard transforms in an interesting manner, are constructed from
eigenvectors of the shift permutation operator that are also simultaneous
eigenvectors of bit-flip (parity) and possess bit-reversal (time-reversal)
symmetry.Comment: Version to appear in J. Phys. A. Added discussions; modified title;
corrected minor error
Synthesis and preclinical validation of novel P2Y1 receptor ligands as a potent anti-prostate cancer agent.
Purinergic receptor is a potential drug target for neuropathic pain, Alzheimer disease, and prostate cancer. Focusing on the structure-based ligand discovery, docking analysis on the crystal structure of P2
Integrated analytical models for flexible manufacturing systems
Product form queueing networks (PFQN) and generalized stochastic Petri nets (GSPN) have emerged as the principal performance modelling tools for flexible manufacturing systems (FMS). In this paper, we present integrated PFQN-GSPN models, which combine the computational efficiency of PFQN and representational power of GSPN by employing the principle of flow-equivalence. We show that FMS that include non-product form characteristics such as dynamic routing and synchronization can be evaluated efficiently and accurately using the integrated models
The role of growth directors in controlling the morphology of hematite nanorods
The control of the growth of hematite nanoparticles from iron chloride solutions under hydrothermal conditions in the presence of two different structure promoters has been studied using a range of both structural and spectroscopic techniques including the first report of photo induced force microscopy (PiFM) to map the topographic distribution of the structure-directing agents on the developing nanoparticles. We show that the shape of the nanoparticles can be controlled using the concentration of phosphate ions up to a limit determined to be ~6 × 10−3 mol. Akaganéite (β-FeOOH) is a major component of the nanoparticles formed in the absence of structure directors but only present in the very early stages (< 8 h) of particle growth when phosphate is present. The PiFM data suggest a correlation between the areas in which phosphate ions are adsorbed and areas where akaganéite persists on the surface. In contrast, goethite (α-FeOOH) is a directly observed precursor of the hematite nanorods when 1,2-diamino propane is present. The PiFM data shows goethite in the center of the developing particles consistent with a mechanism in which the iron hydroxide re-dissolves and precipitates at the nanorod ends as hematite
Spawning periodicity of the ribbon fish, Trichiurus lepturus (F.), with a note on its rate of growth
The spawning periodicity of Trichiurus lepturus is briefly re-examined here in tlie
light of certain recent observations. It is seen that this species spawns more than once
in a year along the Madras coast and the two seasons are roughly around May-June and
later in November-December. This fact also leads to a revision in the interpretation
of the rate of growth of the fish. It is now estimated that the fish at the end of
one year attains an average of 300 mm in length and that those above about 900 mm
are just over four years
The present status of ribbonfish fishery in India
The ribbonfishes, of the family TrichiurkJae, an Important
group of food fishes in India, registered an average annual
catch of 53.475 tonnes during 1970-81. In this period, forming
4.25% of the total marine fish catch, thsy formed the 7th
exploited fish group in the order of predominance.
There are 8 known ribbonfish species in India (an identification
key to the species is given in the beginning of thearticle)
The information available on the various aspects of biology of
each of these species is summarised, which clearly indicates
that while our knowledge on the biology of Trichiurus lepturua,
Lepturecanthus savale, Eupleurogrammus nwticus and Eupleurogrammus
glossodon is considereble, we know little about
the other species.
Traditionally, the ribbonfishes are caught by boatseines,
shoreseines, bag nets and gill nets, operating from nonpowered
country crafts. But, during the last two decades, the small mechanized vessels (10-15 m long, with 15-100 hp engines)
that are operating otter trawls, too, are increasingly landing
ribbonfish. The fishery is confined to the depth-zone usually
shallower than 50 m. T. lepturus, the most widely distributed,
forms the mainstay of the ribbonfish fishery, contributing to
the bulk of the landings along almost all our coastline. Data
on spatial and seasonal variations in abundance, size and age
composition in the commercial catches and diurnal movements
and depthwise distributions of shoals of this species are
therefore reviewed.
Stock assessment studies show that, in the shelf region
from Ratnagiri on the west coast round to Gulf of Mannar on
the east, there had been an average standing stock of 67,200
tonnes of ribbonfish (mostly L Lepturus) in 1972-75, which is
about 4 times what was actually landed from the region during
the period.
It therefore follows that a doubling of the catch will not
adversely affect the stock in the region. Studies on the population
dynamics of T. lepturus from the Kakinada area during
1967-71 has shown that the fishing mortality and the exploitation
rates are low, at 0.3 and 0.17 respectively. The average
annual stock and average standing stock along the Andhra and
Tamil Nadu coasts are estimated at 85,000 and 48,000 tonnes,
respectively, for T. lepturus, against an estimated annual
average catch of 14,400 tonnes during 1967-71. It thus appears
that the stock of T. lepturus along the east coast also is likewise
underfishad,
The need for extension of fishing operations into the
Exclusive Economic Zone with larger vessels, equipped with
suitable gears like bottom and pelagic trawls, is emphasized-
Suggestions on future lines of research are given
Effect of alkali metal cations on the TiO2 P25 catalyst for hydrogen generation by the photoreforming of glycerol
The effect of three aqueous chloride salts, NaCl, KCl and LiCl, on the photoreforming of glycerol over TiO2, and Pt promoted TiO2 catalysts, has been investigated. At concentrations between 0.01 to 0.05 M an enhancement in activity over the TiO2 catalyst by a factor of ~10 can be ascribed to the presence of the cation, with the effect occurring at increasingly high concentrations of salt in the order L
Functional characterization of HIC, a P2Y1 agonist, as a p53 stabilizer for prostate cancer cell death induction
Background: (1-(2-hydroxy-5-nitrophenyl)(4-hydroxyphenyl)methyl)indoline-4-carbonitrile (HIC), an agonist of the P2Y1 receptor (P2Y1R), induces cell death in prostate cancer cells. However, the molecular mechanism behind the inhibition of HIC in prostate cancer remains elusive. Methods and results: Here, to outline the inhibitory role of HIC on prostate cancer cells, PC-3 and DU145 cell lines were treated with the respective IC50 concentrations, which reduced cell proliferation, adherence properties and spheroid formation. HIC was able to arrest the cell cycle at G1/S phase and also induced apoptosis and DNA damage, validated by gene expression profiling. HIC inhibited the prostate cancer cells' migration and invasion, revealing its antimetastatic ability. P2Y1R-targeted HIC affects p53, MAPK and NF-κB protein expression, thereby improving the p53 stabilization essential for G1/S arrest and cell death. Conclusion: These findings provide an insight on the potential use of HIC, which remains the mainstay treatment for prostate cancer.acceptedVersionPeer reviewe
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