2,646 research outputs found
Broodstock development, breeding, embryonic development and larviculture of spine-cheek anemonefish, Premnas biaculeatus (Bloch, 1790)
The broodstock development, breeding, embryonic development and larviculture of Premnas biaculeatus and different feeding
and envrionmental conditioins are reported for the first tiem. The influence of enriched rotifer (Brachionus rotundiformis,
Brachionus plicatilis) and non-enriched newly hatched Artemia nauplii along with microalgae (Chlorella marina,
Nannochloropsis oculata and Isochrysis galbana) on larval rearing and survival was elucidated. Fishes in the length range of
of 55 to 70 mm (presumptive male) and 120 to 150 mm (presumptive female) were selected for pair formation experiments
along with single host sea anemone Heteractis magnifica. All the 10 pairs started spawning within four months after they
were shifted to the breeding tanks. Eggs were laid in round patches or clutches at intervals of 15 to 20 days with an average
of 2.09 ┬▒ 0.3 spawnings per month per pair giving an annual number of 1752 -11832 eggs per pair. Upon incubation for six
days in complete darkness, 95-98% of the eggs hatched with the peak hatching between 1830 and 1930 hrs. On 20th day
post-hatch (d.p.h.), most of the larvae metamorphosed to juveniles and began to shift from partially pelagic to epibenthic
and the juveniles reached marketable size from 60th d.p.h. onwards
Life history pathways in false clown Amphiprion ocellaris Cuvier, 1830: A journey from egg to adult under captive condition
There is a vast literature on distribution, rearing conditions and
behavioural studies of clownfishes. However, descriptive
information on reproductive behaviour, early developments and
life history pathways of Amphiprion ocellaris are scarce. In this
study, 7 pairs of A. ocellaris having size 89 to 100 mm
(presumptive females) and 40 to 60 mm (presumptive males)
were developed through pair formation to generate information
on breeding and spawning behaviour, egg morphology, and
embryonic, larval, juvenile and adult developments. The
spawning was found to be year-round with reproductive cycle
of 12 to 15 days intervals and laid 300 to 1000 capsule shaped
and adhesive type eggs. The eggs were 1.5-3.0 mm in length
and 0.8-1.84 mm in width containing multiple oil globules of
varying size and were pale yellow or white for initial two days,
turned to black on 3rd to 5th day and silvery on 6th to 7th day
of incubation
A robust sequential hypothesis testing method for brake squeal localisation
This contribution deals with the in situ detection and localisation of brake squeal in an automobile. As brake squeal is emitted from regions known a priori, i.e., near the wheels, the localisation is treated as a hypothesis testing problem. Distributed microphone arrays, situated under the automobile, are used to capture the directional properties of the sound field generated by a squealing brake. The spatial characteristics of the sampled sound field is then used to formulate the hypothesis tests. However, in contrast to standard hypothesis testing approaches of this kind, the propagation environment is complex and time-varying. Coupled with inaccuracies in the knowledge of the sensor and source positions as well as sensor gain mismatches, modelling the sound field is difficult and standard approaches fail in this case. A previously proposed approach implicitly tried to account for such incomplete system knowledge and was based on ad hoc likelihood formulations. The current paper builds upon this approach and proposes a second approach, based on more solid theoretical foundations, that can systematically account for the model uncertainties. Results from tests in a real setting show that the proposed approach is more consistent than the prior state-of-the-art. In both approaches, the tasks of detection and localisation are decoupled for complexity reasons. The localisation (hypothesis testing) is subject to a prior detection of brake squeal and identification of the squeal frequencies. The approaches used for the detection and identification of squeal frequencies are also presented. The paper, further, briefly addresses some practical issues related to array design and placement. (C) 2019 Author(s)
Isolation, identification and culture of the marine rotifer Colurella adriatica Ehrenberg, 1831 (Family: Lepadellidae) from Andaman & Nicobar Islands: A promising live feed for larval rearing of high value shellfishes and finfishes
An extremely small rotifer was isolated from the micro zooplankton
samples collected during February, 2014 from Havelock islands of
Andaman and Nicobar Islands. The species was identified as Colurella
adriatica Ehrenberg, 1831 (Family: Lapadellidae). Its lorica length under
culture period ranged from 47.530 to 98.868 ╬╝m and width from
34.308 to 56.277 ╬╝m. The size of the eggs, neonates and adults are
also documented. Comparison of size of C. adriatica with Brachionus
plicatilis (L type) and B. rotundiformis (S and SS type) revealed that
C. adriatica is smaller in length and width than the SS-type rotifer which
is currently used as a first feed in marine tropical fish larval rearing.
However, the larvae of many marine food fishes including groupers and
high value marine ornamental fishes are unable to consume the SS-type
rotifers as a first feed due to their extremely small mouth gape. The
culture of C. adriatica was carried out using Nannochloropsis oculata
Diet-I), N. oculata and yeast (0.01g/litre) (Diet-II), Yeast (0.01g/litre)
alone (Diet-III). Average population density of C. adriatica with these
diets reached a maximum of 1000 nos. of individuals /ml on 10th day
of culture on feeding with Diet-I; 950 nos. /ml on 14th day (Diet-II) and
650 nos. /ml on 15th day of culture (Diet-III). Diet I &II and Diet II &III
did not show any significant difference (P>0.05) whereas, Diet I and III
showed significant difference (P<0.01). Preliminary studies of
C. adriatica as a feed to the larvae of Stenopus hispidus, Lysmata
amboinensis and Pomacentrus caeruleus showed better survival than
larvae fed with B. routundiformis during first phase of larval rearing
Marine ornamental fishes and their breeding: CMFRI initiatives
The marine ornamental fish trade is a sunrise industry in
aquaculture and has become a growing industry worldwide. As a
result the trade of marine ornamentals has been expanding in
recent years and has grown into a multimillion dollar enterprise
mainly due to the emergence of modern aquarium gadgets and
technologies for setting and maintenance of miniature reef aquaria.
Since the marine ornamental trade is operated throughout the
tropics, the global marine ornamental trade is estimated at US$ 200-
330 million. Since India is endowed with a vast resource potential
of marine ornamentals distributed in the coral seas and rocky
coasts with patchy coral formations and the increasing the demand
in the domestic trade, it appears very much lucrative for India to
venture into this industry
Ethnomedicine Against Jaundice Used by Gond Tribes of Adilabad District, Andhra Pradesh, India
The present investigation was performed in order to enumerate the medicinal plants that gond tribes uses for the treatment of jaundice in Adilabad district, Andhra Pradesh, India. The study revealed that totally 12 plants belonging to 9 families were used to cure jaundice . The plants were used either separately or in combination with some other plant parts.
String spectra near some null cosmological singularities
We construct cosmological spacetimes with null Kasner-like singularities as
purely gravitational solutions with no other background fields turned on. These
can be recast as anisotropic plane-wave spacetimes by coordinate
transformations. We analyse string quantization to find the spectrum of string
modes in these backgrounds. The classical string modes can be solved for
exactly in these time-dependent backgrounds, which enables a detailed study of
the near singularity string spectrum, (time-dependent) oscillator masses and
wavefunctions. We find that for low lying string modes(finite oscillation
number), the classical near-singularity string mode functions are non-divergent
for various families of singularities. Furthermore, for any infinitesimal
regularization of the vicinity of the singularity, we find a tower of string
modes of ultra-high oscillation number which propagate essentially freely in
the background. The resulting picture suggests that string interactions are
non-negligible near the singularity.Comment: Latex, 30pgs; v2. minor clarifications, references adde
Armour Protection and Affordable Protection for Futuristic Combat Vehicles
Protection creates a shift in the internal paradigm of the soldier and leads to multiplied psychological stamina for moving fearlessly in the battlefield which generates a major force-multiplier effect. Hence, the mechanized forces are still likely to be one of the dominant forces on the futuristic battlefield and would be the primary target of enemy forces capable of engaging from tank guns up to 4-5 km in a direct fire mode and up to 8-10 km in an indirect fire modes. Increased protection is possible only using advanced armour technology. Throughout the history of warfare, materials technologies have had a significant impact on land-combat force capabilities. Armour materials have progressed through improvements in metallic systems and development of advanced, lightweight (low areal density) composite materials. The advancements in ceramic systems have further improved the performance. Similarly, the advances in development of explosive reactive armour has generated efficient armour system against all contemporary high explosive antitank (HEAT) ammunition and missile threats for armoured vehicles. Yet, to achieve armour performance exceeding that of the current light combat vehicles and main battle tanks for new vehicular systems, weighing significantly less than the present combat vehicles, advances in new armour materials, systems, and survivability technologies are required. This paper describes various approaches and advancements in the metallic, ceramic, and composite armour materials and new dynamic armour systems that are essential to improve the survivability of armoured vehicles in the futurisitic multi-spectral battlefied scenarios.Defence Science Journal, 2011,┬а61(4), pp.394-402,┬аDOI:http://dx.doi.org/10.14429/dsj.61.36
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