391 research outputs found
Phase transitions and bubble nucleations for a phi^6 model in curved spacetime
Condsidering a massive self-interacting phi ^6 scalar field coupled
arbitrarily to a (2+1) dimensional Bianchi type-I spacetime, we evaluate the
one-loop effective potential. It is found that phi ^6 potential can be
regularized in (2+1) dimensional curved spacetime. A finite expression for the
energy-momentum tensor is obtained for this model. Evaluating the finite
temperature effective potential, the temperature dependence of phase
transitions is studied. The crucial dependence of the phase transitions on the
spacetime curvature and on the coupling to gravity are also verified. We also
discuss the nucleation of bubbles in a phi ^6 model. It is found that there
exists an exact solution for the damped motion of the bubble in the thin wall
regime.Comment: 15 pages, 6 figure
Fishing the marine food web along the Indian coast
The annual mean trophic level (TrL) of marine fish landings along the Indian coast consisting of 53 exploited species/groups was estimated for the period 1950–2002. The landings as well as TrL increased along the northwest (NW) and southwest (SW) coasts. However, increase in the landings was associated with decrease in mean TrL along the east coast, particularly along the southeast (SE) coast at the rate of 0.04 per decade. The increasing trend of the FIB index ceased in the last 5–10 years along three coasts. A backward-bending signature in the landings versus TrL plot for the SE coast in the last 6 years indicates fisheries-induced changes in the ecosystem owing to low productivity of the coastal waters and high density of fishing craft. The landings of most of the large predators increased along the Indian coast, but higher removals appear to have helped proliferation of their prey, the mid-level carnivores. Fishing the food web has been influenced by environmental fluctuations, advanced fishing technologies, and market-driven, deliberate fishing on low-trophic level (TL) invertebrates such as the penaeid prawns
Scaffold-based lung tumor culture on porous PLGA microparticle substrates
Scaffold-based cancer cell culture techniques have been gaining prominence especially in the last two decades. These techniques can potentially overcome some of the limitations of current three-dimensional cell culture methods, such as uneven cell distribution, inadequate nutrient diffusion, and uncontrollable size of cell aggregates. Porous scaffolds can provide a convenient support for cell attachment, proliferation and migration, and also allows diffusion of oxygen, nutrients and waste. In this paper, a comparative study was done on porous poly (lactic-co-glycolic acid) (PLGA) microparticles prepared using three porogens—gelatin, sodium bicarbonate (SBC) or novel poly N-isopropylacrylamide [PNIPAAm] particles, as substrates for lung cancer cell culture. These fibronectin-coated, stable particles (19–42 μm) supported A549 cell attachment at an optimal cell seeding density of 250,000 cells/ mg of particles. PLGA-SBC porous particles had comparatively larger, more interconnected pores, and favored greater cell proliferation up to 9 days than their counterparts. This indicates that pore diameters and interconnectivity have direct implications on scaffold-based cell culture compared to substrates with minimally interconnected pores (PLGA-gelatin) or pores of uniform sizes (PLGA-PMPs). Therefore, PLGA-SBC-based tumor models were chosen for preliminary drug screening studies. The greater drug resistance observed in the lung cancer cells grown on porous particles compared to conventional cell monolayers agrees with previous literature, and indicates that the PLGA-SBC porous microparticle substrates are promising for in vitro tumor or tissue development
Status of marine fish stock assessment in India and development of a sustainability index
India has a coastline of 8129 km. Landings by commercial fishing vessels takes
place at 1332 centres during day and night by 58,911 mechanized craft, 75,591 motorized
(with outboard engine) and 104,270 traditional craft (CMFRI, 2006). Marine fisheries are
an important source of food, employment and foreign exchange. About one million
people work directly in this sector, producing 3 million tonnes annually valued at about 3
billion US by exporting
fish and fishery products. India is among the top ten fish producing countries of the
world, contributing 3.5% to the total world marine fish production. Concerned about
the status of marine fish stocks in the Indian EEZ, the country has put in place
appropriate institutional mechanisms to monitor and forecast fishery yields for the last 25
year
Interferon-inducible guanylate-binding proteins at the interface of cell-autonomous immunity and inflammasome activation
Guanylate-binding proteins (GBPs) are essential components of cell-autonomous immunity. In response to IFN
signaling, GBPs are expressed in the cytoplasm of
immune and nonimmune cells, where they unleash their
antimicrobial activity toward intracellular bacteria,
viruses, and parasites. Recent studies have revealed
that GBPs are essential for mediating activation of the
caspase-1 inflammasome in response to the gram-negative
bacteria Salmonella enterica serovar Typhimurium,
Francisella novicida, Chlamydia muridarum, Chlamydia
trachomatis, Legionella pneumophila, Vibrio cholerae,
Enterobacter cloacae, and Citrobacter koseri. During
infection with vacuolar-restricted gram-negative bacteria,
GBPs disrupt the vacuolar membrane to ensure liberation
of LPS for cytoplasmic detection by caspase-11 and the
noncanonical NLRP3 inflammasome. In response to certain
cytosolic bacteria, GBPs liberate microbial DNA for
activation of the DNA-sensing AIM2 inflammasome.
GBPs also promote the recruitment of antimicrobial
proteins, including NADPH oxidase subunits and
autophagy-associated proteins to the Mycobacteriumcontaining vacuole to mediate intracellular bacterial
killing. Here, we provide an overview on the emerging
relationship between GBPs and activation of the
inflammasome in innate immunity to microbial pathogens.This work was supported by the U.S. National Institutes of Health
(NIH) National Institute of Allergy and Infectious Diseases Grants
AI101935, AI124346; NIH National Institute of Arthritis and
Musculoskeletal and Skin Diseases Grant AR056296; and NIH
National Cancer Institute Grant CA163507 (to T.D.K.); the
American Lebanese Syrian Associated Charities (to T.D.K.); and
the R.G. Menzies Early Career Fellowship from the National
Health and Medical Research Council of Australia (to S.M.M.
Fishery, biology and dynamics of dogtooth tuna, Gymnosarda unicolor (Rüppell, 1838) exploited from Indian seas
Dogtooth tuna, Gymnosarda unicolor (Rüppell, 1838)
(Fig. 1) is a pelagic tuna preferring waters of temperature
between 21 and 26 oC. It is one of the principal species
exploited by hook and line (recreational as well as
commercial fishery) operated in the oceanic region. Meat
of dogtooth tuna is white and so it has great demand and
fetch high price (IUCN, 2011). However, occasional
ciguatera fish poisoning in humans has been reported on
consumption of dogtooth tuna. It is exported in fresh and
frozen state and is used for the production of sashimi,
canned tuna, and pouch products. Most of the world
landings of dogtooth tuna during 1963 -2006 was from the
Indian Ocean. Small scale tuna long lines for the species
operating in the Indian Ocean belong to Taiwan, Srilanka,
Maldives, Japan or Pakista
Indian tuna fishery - production trend during yesteryears and scope for the future
Fishery for tuna and tuna like fishes in the country has been in vogue from time immemorial and presently involves fishery
by coastal based fleets of varying specifications with different craft-gear combinations and longline fishery by large oceanic
fishing vessels. The former undertakes short duration fishing trips and exploit mainly surface tunas in the outer shelf and
adjacent oceanic waters. The tuna landings though nominal during 1950-2005, registered a continuous increase over the
years from a minimum of 848 t (1951) to 46,334 t (2000). With the introduction of targeted fishing for oceanic tunas during
2005-‘06, the landings improved and reached the maximum of 129,801 t in 2008. The fishery was supported by nine species,
five coastal/neritic species and four oceanic species. Coastal tunas formed 57% of the tuna catch during 2006-’10 and was
represented by the little tuna (Euthynnus affinis), frigate tuna (Auxis thazard), bullet tuna (Auxis rochei), longtail tuna (Thunnus
tonggol) and bonito (Sarda orientalis). The oceanic species, which formed 43% of tuna catch, were yellowfin tuna (Thunnus
albacares), skipjack tuna (Katsuwonus pelamis), dogtooth tuna (Gymnosarda unicolor) and bigeye tuna (Thunnus obesus).
Information collected from different sources suggested that longliners operating in Indian EEZ and adjacent international
waters caught around 87,000 t of tuna annually during 2006-'10. Catch was supported by three species dominated by
yellowfin tuna and small proportion of big-eye and dogtooth tuna. Since fishery by coastal based units restricted to small
areas and share of the catch by longliners from EEZ are not clearly known, systematic assessment of tuna stock in Indian
EEZ is very difficult. However, the evaluation of the fishery scenario indicated only limited scope for improving tuna
production from certain areas of coastal waters; whereas enormous scope remain for increasing tuna production from the
oceanic waters of EEZ. However, since tunas being straddling resources shared by several nations, exploitation at one area
will influence the fishery in other areas
Massive Charged Scalar Quasinormal Modes of Reissner-N\"ordstrom Black Hole Surrounded by Quintessence
We evaluate the complex frequencies of the normal modes for the massive
charged scalar field perturbations around a Reissner-N\"ordstrom black hole
surrounded by a static and spherically symmetric quintessence using third order
WKB approximation approach. Due to the presence of quintessence, quasinormal
frequencies damp more slowly. We studied the variation of quasinormal
frequencies with charge of the black bole, mass and charge of perturbating
scalar field and the quintessential state parameter.Comment: 9 pages, 9 figures and one tabl
Fishery, biology and stock structure of skipjack tuna, Katsuwonus pelamis (Linnaeus, 1758) exploited from Indian waters
Global catches of skipjack tuna have been steadily
increasing since 1951, reaching a peak in 2009 at 25, 99,681 t
(Fig.1). Most of the catches were reported from the fishing
areas 71, 51, 61 and 34 (FA0, 2011). Globally skipjack
tuna is caught at the surface, mostly with purse seines and
pole and lines and to a small extent by gillnets, troll lines
and longlines. Gears like purse-seine and very long gillnets
enabled few nations to augment their production, whereas
traditional pole and line nations suffered heavily
- …