733 research outputs found
Lie Symmetry Analysis of the Black-Scholes-Merton Model for European Options with Stochastic Volatility
We perform a classification of the Lie point symmetries for the
Black--Scholes--Merton Model for European options with stochastic volatility,
, in which the last is defined by a stochastic differential equation
with an Orstein--Uhlenbeck term. In this model, the value of the option is
given by a linear (1 + 2) evolution partial differential equation in which the
price of the option depends upon two independent variables, the value of the
underlying asset, , and a new variable, . We find that for arbitrary
functional form of the volatility, , the (1 + 2) evolution equation
always admits two Lie point symmetries in addition to the automatic linear
symmetry and the infinite number of solution symmetries. However, when
and as the price of the option depends upon the second
Brownian motion in which the volatility is defined, the (1 + 2) evolution is
not reduced to the Black--Scholes--Merton Equation, the model admits five Lie
point symmetries in addition to the linear symmetry and the infinite number of
solution symmetries. We apply the zeroth-order invariants of the Lie symmetries
and we reduce the (1 + 2) evolution equation to a linear second-order ordinary
differential equation. Finally, we study two models of special interest, the
Heston model and the Stein--Stein model.Comment: Published version, 14pages, 4 figure
Biomarkers of environmental contaminants in field population of green mussel (Perna viridis) from Karnataka-Kerala coast (South West coast of India)
The green mussel Perna viridis was sampled
from relatively clean and contaminated sites along the
Kartanata-Kerala coast (south west coast of India) to study
the tissue concentration of trace metals and biological
responses to stress (biomarkers) such as sister chromatid
exchange (SCE), chromosomal aberration, micronucleus
(MN) test, hemic neoplasia (HN), Chromotest (Ames test)
and comet assay
Heavy metal distribution in the biotic and abiotic matrices along Karnataka coast, west coast of India
Sediment and soft tissue of bivalve samples collected from various sites of Karnataka coast were
analysed for the estimation of the nanaal and anthropogenic heavy metal fluxes. Seasonal variations of
heavy metals in sediment and bivalves collected from selected hot spots from Binage, Karwar and
Thannirbavi, Mangalore were monitored. High concentrations of Hg was observed in the environment
near' the vicinity of a caustic soda plant at Binage, Karwar, indicating Hg pollution. Total Hg
concentration in the tissue of oysters sampled from a contaminated stream from the above site, exceeded
the safe limit of 0.5 ilg g.1 wet weight. The base-line heavy metal concentrations in sediment and
bivalves from selected sites of coastal Karnataka are presented
Accumulation of trace metals in green mussel Perna viridis in the shellfish harvesting environment along southern Karnataka coast
The levels of trace metals, Cd, Pb, Cu, Zn, Ni and Fe in seawater and their bioaccumulation in green mussel Perna viridis were examined in two shellfish harvesting environments, Someshwara and Surathkal, along the southern Karnataka coast. In seawater, the concentration of trace metals analysed were below the levels causing harmful effects on the larvae and adult mussels, set by the European Council Directive 79/923/EEC. The Fe, Ni, Cd and Zn levels in mussel tissue from Surathkal were relatively higher when compared to that of mussel tissue samples from Someshwara while Cu and Pb levels were lower. The mean tissue concentrations of trace metals in the soft tissue of P. viridis from shellfish waters were found to be safe and
below the permissible concentrations for seafood (US FDA and WHO) as well as EU limits in marine products
On two finless porpoise Neophocaena phocaenoides landed at Malpe Fishing Harbour, Udupi district, Karnataka.
Two finless porposies Neophocaenan phocaenoides were caught by purseseine and landed at Malpe Fishing Harbour On 06-11-2003. Both the animals were auctioned for Rs. 660.Enquiries with the purseseiner which brought the
porposies, revealed that they were caught from a depth
of 15 m along with the catch of sardine, mackerel and
rainbow sardine. The mesh size of the purseseine was 18 mm
Influence of Environmental Factors on Growth Rate of Crassostrea madrasensis (Preston) in Suspended Culture
Growth response of Crassostrea madrasensis to varying environmental factors in
the Mulki estuary of Karnataka was investigated from April 2004 to March 2005. Temperature,
salinity, pH, particulate organic matter (POM), particulate inorganic matter
(PIM), total particulate matter (TPM) and chlorophyll a (Chl a) levels were correlated
with growth in shell length. Marked seasonal patterns in growth rate were observed in
relation to changes in environmental factors. Growth curve indicated a rapid phase
(16.21┬▒1.2 mm month-1) initially (May-June) followed by a slow phase (0.8┬▒0.52 mm
month-1) coinciding with the drop in salinity (August-September). Considering the temporal
variations of environmental factors, their influence on growth rate was analysed
seasonally. The growth rate was significantly correlated with Chl a concentrations in all
the seasons. A pronounced seasonal cycle was noticed in Chl a levels resulting from
blooms in pre-monsoon (April-May) and post-monsoon (October) seasons
Heavy metal concentration in sea water, sediment and bivalves off Tuticorin
Concentration of heavy metals Cd, Cu, Fe, Mn, Ni, Pb and Zn in sea water, sediment and bivalve
samples from three stations was studied for one year along Tuticorin coast. The concentration was
in the order of Fe>Mn>Zn>Cu>Pb>Cd>Ni. Generally the concentration of Fe was very high in the
sediment and bivalves when compared to earlier studies from other areas along the Indian coast. High
concentration of Fe, Mn, Cu, Pb and Zn was observed during monsoon season. One way ANOVA
indicated statistically significant differences (p<0.01) among the samples in the concentration of Cu,
Fe, Mn, Pb and Zn. Except for Cd and Cu, no significant difference was noticed in the seasonal variation
of other metals
Timing Offset Calibration of CZTI instrument aboard ASTROSAT
The radio as well as the high energy emission mechanism in pulsars is yet not
understood properly. A multi-wavelength study is likely to help in better
understanding of such processes. The first Indian space-based observatory,
ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum
from infra-red (1300 ) to hard X-ray (380 KeV). Cadmium Zinc Telluride
Imager (CZTI), one of the five instruments is a hard X-ray telescope functional
over an energy range of 20-380 KeV. We aim to estimate the timing offset
introduced in the data acquisition pipeline of the instrument, which will help
in time alignment of high energy time series with those from two other
ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and
the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with
nearly aligned radio and hard X-ray pulse profiles. We use simultaneous
observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar
was especially observed using the ORT with almost daily cadence to obtain good
timing solutions. We also supplement the ORT data with archival FERMI data for
estimation of timing noise. The timing offset of ASTROSAT instruments was
estimated from fits to arrival time data at the ASTROSAT and the radio
observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to
be -4716 50 . The corresponding offset with the ORT was -29639
50 . The offsets between the GMRT and Fermi-LAT -5368 56
. (Abridged)Comment: 6 pages, 5 figures, 2 tables, Revised and Updated, accepted for
publication in A&
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