12,917 research outputs found
Evaluation of a simple tagging method to monitor the growth of endangered species of seahorse
Identification of an individual seahorse is important
for captive breeding and conservation studies. A simple
and cost-effective tagging method was devised to suit
the rigid body structure and small fins of Hippocampus
kuda. The first generation sexually matured individuals
(452 numbers) were tagged using plastic strips
tied around the neck. No significant differences (P >
0.05) in growth between the tagged and untagged
groups were noted. All the tags persisted for one year
without any perceptible changes in sexual and social
behaviour
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Measurements of I/SVOCs in biomass-burning smoke using solid-phase extraction disks and two-dimensional gas chromatography
Biomass-burning organic-aerosol (OA) emissions are known to exhibit semi-volatile behavior that impacts OA loading during plume transport. Because such semi-volatile behavior depends in part on OA composition, improved speciation of intermediate and semi-volatile organic compounds (I/SVOCs) emitted during fires is needed to assess the competing effects of primary OA volatilization and secondary OA production. In this study, 18 laboratory fires were sampled in which a range of fuel types were burned. Emitted I/SVOCs were collected onto Teflon filters and solid-phase extraction (SPE) disks to qualitatively characterize particulate and gaseous I/SVOCs, respectively. Derivatized filter extracts were analyzed using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC├ЧGC-TOFMS). Quality control tests were performed using biomass-burning relevant standards and demonstrate the utility of SPE disks for untargeted analysis of air samples. The observed chromatographic profiles of I/SVOCs in coniferous fuel-derived smoke samples were well correlated with each other, but poorly correlated with other fuel types (e.g., herbaceous and chaparral fuels). Emissions of benzenediol isomers were also shown to be fuel dependent. The combined Teflon and SPE filter data captured differences in gas-particle partitioning of the benzenediol isomers, with hydroquinone having a significantly higher particle-phase fraction than catechol due to its lower volatility. Additionally, the speciated volatility distribution of I/SVOCs in smoke from a rotten-log fire was estimated to evaluate the composition of potentially volatilized primary OA, which was entirely attributed to oxygenated (or other heteroatomic) compounds. The isomer-dependent partitioning and the speciated volatility distributions both suggest the need for better understanding of gas-phase and heterogenous reaction pathways of biomass-burning-derived I/SVOCs in order to represent the atmospheric chemistry of smoke in models
Breeding, rearing and sea-ranching of chanks
The heavy demand, concomitant with specific expldltattoti as
welt as bottom trawling led to habitat destruction and depletion oj
sacred chank Xancus pyrum. Experiments conducted to study the
natural growth and breeding aspects indicate that during March
and November, the chanks release egg capsules containing fertilised
eggs. The deuelopment is direct and the babies hatch out after 32
to 35 days of incubation at an ambient temperature 30.7┬░C. During
their early stages, they feed on oligochaete and polychaete worms.
From an initial 9.09 mm, they grow to 62.23mm In an year, while
the MSD increased to 27.40 mm. They weighedfrom 0,14 to 32.36 g
during one year. Chanks are non-migratory and their natural growth
in sea indicated an average MSD growth ofS.Omm/yearforXancus
pyrum var. acuta
Species-specific proteins in closely-related seahorses
Non-denatured polyacrylanlide gel shows the respective species-specific characteristics on the muscle protein
of' Hippocampus kuda and N. trirnacrtiahs. Two
proteins; of molecular weight 66.8 and 39.8 kDa were
found exclusively in 11. kuda. These constituted about
69.8 and 16.2% respectively of its protein. In M. trintucuirtus,
two other specific proteins with molecular
weight of 674.3 and 50.5 kDa were recorded, which
constituted 46.0 and 7.5% respectively of its protein.
These species-specific proteins are important for species
identification, which paves avenues for further
characterization and upgrading of the available information
on seahorse taxonomy
Faster Separators for Shallow Minor-Free Graphs via Dynamic Approximate Distance Oracles
Plotkin, Rao, and Smith (SODA'97) showed that any graph with edges and
vertices that excludes as a depth -minor has a
separator of size and that such a separator can be
found in time. A time bound of for
any constant was later given (W., FOCS'11) which is an
improvement for non-sparse graphs. We give three new algorithms. The first has
the same separator size and running time O(\mbox{poly}(h)\ell
m^{1+\epsilon}). This is a significant improvement for small and .
If for an arbitrarily small chosen constant
, we get a time bound of O(\mbox{poly}(h)\ell n^{1+\epsilon}).
The second algorithm achieves the same separator size (with a slightly larger
polynomial dependency on ) and running time O(\mbox{poly}(h)(\sqrt\ell
n^{1+\epsilon} + n^{2+\epsilon}/\ell^{3/2})) when . Our third algorithm has running time
O(\mbox{poly}(h)\sqrt\ell n^{1+\epsilon}) when . It finds a separator of size O(n/\ell) + \tilde
O(\mbox{poly}(h)\ell\sqrt n) which is no worse than previous bounds when
is fixed and . A main tool in obtaining our results
is a novel application of a decremental approximate distance oracle of Roditty
and Zwick.Comment: 16 pages. Full version of the paper that appeared at ICALP'14. Minor
fixes regarding the time bounds such that these bounds hold also for
non-sparse graph
Onset of sexual maturity in captivereared endangered Indian seahorse, Hippocampus kuda
The endangered Indian seahorse, Hippocampus kuda
successfully reared in captive conditions for more
than two years, repeatedly spawned and produced F2
generations. In F1 males, brood pouch started developingfrom 55 to 60 days of birth. The courtship behaviour
was noted 30 days subsequently and males
started receiving eggs in their pouch when their body
length attained 101.0 ┬▒ 2.0 mm. Females started transferring
eggs into the male brood pouch when their
body length reached 110.0 ┬▒ 2.0 mm. The sexual maturity
of male was earlier than that of female. Compared
to the age (in days), the size was inferred as a reliable
factor to predict the onset of maturity in this species
Captive Breeding and Nursery Rearing of the Indian Seahorse, Hippocampus kuda (Teleostei: Syngnathidae)
Breeding of laboratory-reared 21 pairs of broodstock Hippocampus kuda
(Bleeker 1852) and rearing of their young ones indicated that 262.00 ┬▒ 59.00 offsprings
were released during each spawning. A newly born seahorse was (mean ┬▒ SE) 7.83 ┬▒ 0.11
mm in length with a weight of 1.17 ┬▒ 0.009 mg. It could attain a mean length of 31.14 ┬▒
0.66 mm with a mean weight of 16.13 ┬▒ 0.60 mg in 30 days when fed ad libitum with
Artemia nauplii. The mean survival per brood cycle was enhanced to 65.22 ┬▒ 1.87% from
almost less than 1.0% by improving the rearing conditions
Antibacterial activity of aqueous extract from selected macroalgae of southwest coast of India
Aqueous extract of seven species of marine macroalgae were screened for their antimicrobial
potency against ten pathogenic bacterial strains. Ulva fasciata, Gracilaria corticata, Sargassum
wightii and Padina tetrastromatica showed significantly higher activity against 70% of the
tested bacterial isolates. The maximum zone of inhibition was noted for the red alga G.corticata
against Proteus mirabilis (17mm) and brown alga P. tetrastromatica against the pathogens
Staphylococcus aureus and Vibrio harveyi (15mm). The general trend of inhibitory activity
was higher towards Gram negative bacteria
Polymicrobial skin lesions in the red spot emperor, Lethrinus lentjan (Lacepede 1802) during mass incursion towards shore along Kanyakumari coast, south India
Mass incursion of fishes with polymicrobial skin lesions, fin erosions and scale loss was recorded in the red spot emperor
Lethrinus lentjan (Lacepede 1802) along the Kanyakumari coast, south India during August 2009. An estimated 2.5 t of fish,
mostly the red spot emperors were found to migrate in live condition to the shore areas in a stressful state. Microbiological
analyses of tissue from sampled fishes revealed three distinct types of bacterial colonies forming 5.2 x 105 CFU g-1 of the
infected tissues. The predominant bacterial colonies were characterized as Aeromonas sp. (70.0%) followed by Flavobacterium
sp. (20%) and Vibrio sp. (10%). The Aeromonas isolate was highly susceptible to norfloxacin while the Flavobacterium and
Vibrio isolates were susceptible to chloramphenicol. The Aeromonas and Vibrio isolates exhibited protease and amylase
enzyme activities in vitro, suggesting their possible role in the progression of skin lesions and scale loss. The possibilities of
ambient unknown stressors weakening the fish and subsequent infections by these bacterial isolates are discussed
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