1,471 research outputs found
Freezing of viable embryos and larvae of marine shrimp, Penaeus semisulcatus de Haan
Although sperm cryopreservation has been carried
out successfully in a number of commercially
important aquatic species, particularly in some
teleost fish (see review of Rana in Muir & Roberts
1993) and also shellfish (Subramoniam 1993), the
technology is still not at the stage of advanced
commercial application that is seen in domestic
mammals. Cryopreservation of eggs and embryos,
of aquatic animals however, is a virgin field in
cryobiology and has not yet received any appreciable
amount of attention. The first successful attempt at
the cryopreservation of embryos of sea urchin was
reported by Asahina & Takahashi (1978). Later Zell
(1978) and Erdahl & Graham (1980) have reported
preliminary attempts to freeze the eggs of rainbow
trout
Stormwater sand filters in water-sensitive urban design
This paper investigates the suitability of sand filters for harvesting and treating stormwater for non-potable reuse purposes. A stormwater sand filtration device was constructed in a small urban catchment in Sydney, Australia. A sand filter is typically used in water-sensitive urban design (WSUD) as a component of a treatment train to remove pollution from stormwater before discharge to receiving waters, to groundwater or for collection and reuse. This paper describes an 18 month field study undertaken to determine the effectiveness and pollutant removal efficiency of a sand filter, and the differences in the pollutant removal efficiency of two grades of sand. A comparison of pollutant removal with previous literature on sand filters showed similar efficiencies but nutrient removal was higher than expected. A further unexpected result was that the coarse filter media performed as well as the fine media for most pollutant types and was superior in suspended solids removal. Improved modelling equations for predicting suspended solids and total phosphorus removal in sand filters are also presented in this paper
In vitro propagation of Alternanthera sessilis (sessile joyweed), a famine food plant
A complete protocol for micropropagation of Alternanthera sessilis using leaf explants was developed. Leaf explants from A. sessilis established on Murashige and Skoog medium were treated with various concentrations and combinations of auxins and cytokinins to determine the best method for callus formation, shoot regeneration and root formation. MS medium supplemented with 1 mg/l BAP and 1 mg/l 2,4-D was determined to be the most suitable for callus induction. After 2 weeks, the callus wasthen transferred to shooting media which consisted of half strength MS basal medium, 1 mg/l IAA and 1 mg/ l BAP. After 4 weeks, structures were observed with their basal ends embedded on the callus. These structures turned into green colored shoot buds. MS medium supplemented with 1 mg/l IAA and 1 mg/l BAP showed maximum shoot multiplication. For rooting, the optimal medium was half strength MS medium supplemented with 1 mg/l IBA. Rooted plantlets were then transferred to sunbag vessels which provided the high humidity environment. The hardened plants were then successfullyestablished in the soil medium and can function in the natural environment
Chemical-assisted physico-biological water mining system
Water mining is the process of extracting valuable water from a sewerage network by treating raw sewage to high standards. A range of commercially viable water mining treatment technologies are now available to treat sewage to specified water quality targets. Most of these technologies have minimal plant footprint requirements, making them suitable for decentralised operations. This paper discusses a hybrid water mining system that includes chemically assisted fine solids separation followed by a biological treatment process. Results from the first proof testing of this water mining system in Sydney, Australia are presented. The results confirm the suitability of the hybrid system for producing high-quality water for non-potable reuse
Prospects of Grouper Culture in India
The "Groupers" of the genus Epinephelus are excellent marine food fishes in the Indo Pacific and Carribean regions and have assumed importance for commercial culture in recent year
Formation of lead lanthanum zirconate titanate films by heat treatments
Lead lanthanum zirconate titanate (PLZT) also called lanthanum doped PZT films were deposited by RF magnetron sputtering. PLZT in the perovskite phase is required to obtain a film with a large electro-optic effect. It can also be used as a ferroelectric and piezoelectric material. However films that have not been heat treated either during or after deposition are typically in the pyrochlore phase. Perovskite PLZT films obtained by heating the substrate during sputtering showed little evidence of cracks in the films sputtered without heating the substrate were not in the Perovskite phase and post deposition annealing was required to do so. Both furnace and rapid thermal annealing were investigated but in both cases cracks formed in the films to various degrees. Such films are unsuitable for optical device fabrication. To determine the orientation of PLZT films X-ray diffraction (XRD) spectras were obtained and compared. Samples were prepared on silicon substrates which had a thin film of 20 nm Ti/100 nm Pt deposited by electron beam evaporation. Sputtering was done in an argon atmosphere using a PLZT (9/65/35) target. Thicknesses of 1 mum were obtained. Some samples were heated during sputtering up to a temperature of 650 degC. Annealing temperatures were varied from 500 to 750 degC. The best results (determined by XRD) were obtained for RTA at 750 degC for 10 minutes in air. XRD spectra of before and after annealing show a significant increase in the Perovskite peaks. The patterning of these films to form optical waveguides by ion beam etching is also presented. The samples were patterned with photoresist masks and ion beam etched using argon at a gun voltage of 500
Implementation of Fault-tolerant Quantum Logic Gates via Optimal Control
The implementation of fault-tolerant quantum gates on encoded logic qubits is
considered. It is shown that transversal implementation of logic gates based on
simple geometric control ideas is problematic for realistic physical systems
suffering from imperfections such as qubit inhomogeneity or uncontrollable
interactions between qubits. However, this problem can be overcome by
formulating the task as an optimal control problem and designing efficient
algorithms to solve it. In particular, we can find solutions that implement all
of the elementary logic gates in a fixed amount of time with limited control
resources for the five-qubit stabilizer code. Most importantly, logic gates
that are extremely difficult to implement using conventional techniques even
for ideal systems, such as the T-gate for the five-qubit stabilizer code, do
not appear to pose a problem for optimal control.Comment: 18 pages, ioptex, many figure
On the large sunfish landed near Mandapam
A sunfish, Ranzania laevis (Pennant) measuring
660 mm total length was caught on 5.3.1998 in shoreseine
near Mandapam in Palk Bay. In fresh condition
its colour was bluish with dark above and pale white
below with small hexagonal plates and smooth skin.
Six streaks of lighter colour bordered with dark descended
from snout to gill slits and curved downwards to
the ventral profile. The posterior three streaks were
branched with dark spots. The lips were produced forward
beyond the teeth closing as a vertical slit
The plasma nitric oxide and homocysteine levels and their association with insulin resistance in South Indian women with polycystic ovary syndrome
Background: Women with polycystic ovary syndrome (PCOS) exhibit features of the metabolic syndrome apart from low-grade chronic inflammation and endothelial dysfunction and may be at increased risk for cardiovascular disease (CVD). The Nitric oxide (NO) and Homocysteine (Hcy) are important plasma markers of endothelial dysfunction, an early marker of atherosclerosis. There are no Indian studies on NO and Hcy levels in women with PCOS and their association with Insulin Resistance (IR). Therefore the present study is to estimate plasma levels of NO and Hcy in south Indian women with PCOS and association with insulin resistance.Methods: 104 women with PCOS and 95 healthy age matched control subject were enrolled in the study. Standard physical methods and Chemiluminescent Immunoassay technique were employed for estimation of Anthropometric parameter and plasma sex hormones respectively. Fasting insulin, glucose, NO and Hcy were measured by standard methods. Insulin resistance was evaluated by using Homeostasis Model Assessment for Insulin Resistance (HOMA- IR)Results: Women with PCOS had significantly higher insulin resistance (P<0.01), Hcy (p<0.05) and lower NO levels (P<0.05), IR was positively correlated with Hcy (r= 0.610, p<0.01) and negatively correlated with NO (r= -0.285; p<0.01)Conclusions: Our data revealed that South Indian women with PCOS had elevated IR and homocyeteine and lowered NO levels
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