12 research outputs found
Application of Some Herbal Extracts and Calcium as an Antidote to Counteract the Toxic Effects of Cypermethrin and Carbofuran in Indian Major Carp, Labeo Rohita
Strategies to control invasion of Sailfin Armoured Catfish, Pterygoplichthys spp. in wastewater-fed aquaculture bheries of East Kolkata Wetland, India with suggestion of a modified barrier based on the biological and behavioural characteristics
Sailfin armoured catfish (Pterygoplichthys spp.), an alien invasive species of family Loricariidae has invaded extensively in wastewater-fed large aquaculture ponds (locally called âbheriesâ) of East Kolkata Wetlands (EKW), West Bengal, India. As there is no viable controlling method at present, commonly these fishes are removed by different physical methods and discarded. In the present study, we investigated the effectiveness and suitability of different in-practice Pterygoplichthys spp. control methods, based on on-field sampling, biological and behavioural study of the fish and also response analysis of the stakeholderâs of EKW. The results indicate that in-practice eradication efforts, like ârepeated seine nettingâ with or without removal of Eichhornia sheath of the pond periphery and âdewatering of pondâ aiming to reduce or eradicate Pterygoplichthys spp., are not fully effective, because of the capture avoidance ability and burrowing habit of these fishes. We found deep and branching burrows of Pterygoplichthys spp. in aquaculture ponds of EKW, with maximum burrow depth of 58 cm, and water in that burrows even after 12 days of dewatering. Hence, it is suggested stakeholders to keep dewatered pond exposed to sunlight for at least four weeks or above to ensure complete water-out from the burrows in which Pterygoplichthys spp. take shelter or lay their eggs. âMultilayer bamboo fencingâ or âcombination of bamboo fencing and net barrierâ use by the stakeholders of EKW to prevent intrusion or re-intrusion of Pterygoplichthys spp. were found only partially effective, because of the capability of these fishes to damage net-blocking through their hard dorsal and pectoral spines or entry through the holes dug across the barrier in beneath or banks of the sewage intake channel. Based on learning on the biological and behavioural characteristics of Pterygoplichthys spp., we then suggested a modified version of barrier to the stakeholderâs of EKW, incorporating a sewage feeder pipeline, a concrete collection chamber with size separation arrangement made of hard materials like wire mesh and a dam of specific dimensions across the channel, for effective prevention of intrusion of these fishes in their aquaculture bheries
Constraining R-parity violating couplings using dimuon data at Tevatron Run-II
The dimuon plus dijet signal is analyzed in the top squark pair production at
Tevatron Run-II experiment and the total event rate is compared with the
existing dimuon data. This comparison rules out top squark mass upto 188(104)
GeV for the branching fraction 100%(50%) of top squark decay into the muon plus
quark via lepton number violating coupling. Interpretation of this limit in the
framework of R-parity violating(RPV) SUSY model puts limit on relevant RPV
coupling for a given top squark mass and other supersymmetric model parameters.
If \MST \lsim 180 GeV we found that the RPV couplings are roughly restricted
to be within which is at the same ballpark value obtained from
the neutrino data. The limits are very stringent for a scenario where top
squarks appear to be the next lightest supersymmetric particles.Comment: 7 pages, 3 figures,added minor clarifications,version to appear in
Phys. Lett.
A RETROSPECTIVE STUDY ON THE INCIDENCE OF FISH DISEASES AND USE OF THERAPEUTANTS IN AQUACULTURE FARMS OF MOYNA, THE âFISHERIES HUBâ OF WEST BENGAL, INDIA
The present study depicts the disease incidences in the aqua farms of Moyna, West Bengal, India, during 2018-
2020 and aqua-drugs used by farmers to combat diseases. A total of 132 fish disease incidences were reported, among which
parasitic diseases were the most common (53.03%) followed by bacterial diseases (27.27%), diseases due to poor nutrition and
environmental fluctuations (10.61%), and fungal diseases (9.09%), respectively. Out of the 53.03% parasitic disease incidences
reported, Argulus (22.86%), Dactylogyrus (17.14%), Gyrodactylus (10.00%), Myxospores (10.00%), Lernaea (8.57%),
Ichthyophthirius (5.71%) and Trichodina (4.29%) were the major disease-causing parasites. Among bacteria,
Pseudomonas spp. and Aeromonas spp. were the most dominant genera encountered in diseased fish. Labeo catla was the most
susceptible fish species followed by Labeo rohita, and Cirrhinus mrigala. Seasonal influence in disease occurrence was noticed.
Monsoon and winter were favorable seasons for disease outbreaks. The influence of water quality parameters like hardness, pH,
ammonia, total dissolved solids of water, and total organic carbon of sediment had a significant correlation with parasite
abundance. Farmers of Moyna were observed to use a wide range of chemicals and aqua-drugs to control diseases and related
problems. The majority of the fish farms of Moyna were found using feed additives and supplements (32.00%) followed by
sanitizers and disinfectants (24.00%), probiotics (17.00%), anti-parasitic drugs (11.00%), antibiotics (8.00%), and other
chemicals (20.00%). Lime (calcium carbonate) and zeolite along with sodium chloride, potassium permanganate, formalin, and
calcium hypochlorite were extensively used as disinfectants in Moyna. Farmers being unaware of the adverse consequences of
using chemicals and aqua-medicines are fully dependent on private aquaculture consultants for time-to-time advice, which may
have augmented their indiscriminate use. Initiative for the implementation of better management practices by creating awareness
among farmers and adopting strict aquaculture policy guidelines might improve the scenario
Cosmological constraints on R-parity violation from neutrino decay
If the neutrino mass is non-zero, as hinted by several experiments, then
R-parity-violating supersymmetric Yukawa couplings can drive a heavy neutrino
decay into lighter states. The heavy neutrino may either decay radiatively into
a lighter neutrino, or it may decay into three light neutrinos through a
Z-mediated penguin. For a given mass of the decaying neutrino, we calculate its
lifetime for the various modes, each mode requiring certain pairs of
R-parity-violating couplings be non-zero. We then check whether the calculated
lifetimes fall in zones allowed or excluded by cosmological requirements. For
the latter case, we derive stringent new constraints on the corresponding
products of R-parity-violating couplings for given values of the decaying
neutrino mass.Comment: 13 pages, Latex, uses axodraw.sty; version to appear in Physical
Review
Neutrino masses in R-parity violating supersymmetric models
We study neutrino masses and mixing in R-parity violating supersymmetric
models with generic soft supersymmetry breaking terms. Neutrinos acquire masses
from various sources: Tree level neutrino--neutralino mixing and loop effects
proportional to bilinear and/or trilinear R-parity violating parameters. Each
of these contributions is controlled by different parameters and have different
suppression or enhancement factors which we identified. Within an Abelian
horizontal symmetry framework these factors are related and specific
predictions can be made. We found that the main contributions to the neutrino
masses are from the tree level and the bilinear loops and that the observed
neutrino data can be accommodated once mild fine-tuning is allowed.Comment: 18 pages; minor typos corrected. To be published in Physical Review
Probing R-parity violating models of neutrino mass at the Tevatron via top Squark decays
We have estimated the limiting branching ratio of the R-parity violating
(RPV) decay of the lighter top squark, \tilde t_1 \ar l^+ d ( or
and d is a down type quark of any flavor), as a function of top squark
mass(\MST) for an observable signal in the di-lepton plus di-jet channel at
the Tevatron RUN-II experiment with 2 fb luminosity. Our simulations
indicate that the lepton number violating nature of the underlying decay
dynamics can be confirmed via the reconstruction of \MST. The above decay is
interesting in the context of RPV models of neutrino mass where the RPV
couplings () driving the above decay are constrained to be
small (\lsim 10^{-3} - 10^{-4} ). If is the next lightest super
particle - a theoretically well motivated scenario - then the RPV decay can
naturally compete with the R-parity conserving (RPC) modes which also have
suppressed widths. The model independent limiting BR can delineate the
parameter space in specific supersymmetric models, where the dominating RPV
decay is observable and predict the minimum magnitude of the RPV coupling that
will be sensitive to Run-II data. We have found it to be in the same ballpark
value required by models of neutrino mass, for a wide range of \MST. A
comprehensive future strategy for linking top squark decays with models of
neutrino mass is sketched.Comment: 28 pages, 14 Figure