Mixed culture of fishes in seasonal ponds through fertilization and feeding

A study on mixed culture of mirror carp (Cyprinus carpio Lin.), tilapia (Oreochromis niloticus Lin.), silver carp (Hypophthalmicthys molitrix Val.) and Thai sharpunti (Puntius gonionotus Bleeker) in the ratio of 1:2:2:5 was conducted in 12 seasonal mini ponds (30 m² each) for 105 days. There were six treatments each with two replicates and each pond was stocked with a total of 100 fishes. Rice bran and mustard oil cake were used as supplemental feed either in combination or alone in presence or absence of fertilizer. Fertilizers were used in the form of organic, inorganic or both. The best growth performance of mirror carp, tilapia and Thai sharpunti was obtained in treatment III which received both fertilizer (organic+inorganic) and rice bran while the highest growth of silver carp was obtained in treatment VI receiving only inorganic fertilizer. However, the overall best production (2450 Kg/ha) and economic return for the culture period was obtained in treatment VI followed by treatment III. The results are discussed in the light of water quality parameters.

Cryopreservation of rhesus macaque (Macaca mulatta) spermatozoa and their functional assessment by in vitro fertilization

Although spermatozoa from several species of nonhuman primates have been cryopreserved, there has been no report of success with rhesus macaque spermatozoa as judged by functional assays. Two Tris-egg yolk freezing media. TEST and TTE. which have: been successfully used for cynomolgus macaque (Macaca fascicularis) spermatozoa, were compared for cryopreservation of spermatozoa From four rhesus macaques (Macaca mulatta). The postthaw motility (percentage and duration) of spermatozoa cryopreserved in TTE was much higher than that for spermatozoa cryopreserved in TEST. The function of sperm cryopreserved in TTE was evaluated by in vitro fertilization or oocytes collected from gonadotropin-stimulated prepubertal rhesus macaques. Of the inseminated oocytes. 82 +/- 13% were fertilized and 63 +/- 22 and 39 +/- 21% of the resulting zygotes developed into morulae and blastocysts. respectively. These results indicate that rhesus macaque spermatozoa can be effectively cryopreserved in TTE medium. This finding will facilitate the application of in vivo and in vitro assisted reproductive technologies in this species. (C) 2001 Academic Press.

Broadband ultrafast pulse generation with double wall carbon nanotubes

Materials with nonlinear optical properties are much sought after for ultrafast photonic applications. Mode-locked lasers can generate ultrafast pulses using saturable absorbers[1]. Currently, the dominant technology is based on semiconductor saturable absorber mirrors (SESAMs). However, narrow tuning range (tens of nm), complex fabrication and packaging limit their applications[2]. Single wall nanotubes (SWNTs) and graphene offer simpler and cost-effective solutions[1]. Broadband operation can be achieved in SWNTs using a distribution of tube diameters[1,3], or by using graphene[4-8], due to the gapless linear dispersion of Dirac electrons[8,9]. © 2011 IEEE.

The double dance of agency: a socio-theoretic account of how machines and humans interact

The nature of the relationship between information technology (IT) and organizations has been a long-standing debate in the Information Systems literature. Does IT shape organizations, or do people in organisations control how IT is used? To formulate the question a little differently: does agency (the capacity to make a difference) lie predominantly with machines (computer systems) or humans (organisational actors)? Many proposals for a middle way between the extremes of technological and social determinism have been put advanced; in recent years researchers oriented towards social theories have focused on structuration theory and (lately) actor network theory. These two theories, however, adopt different and incompatible views of agency. Thus, structuration theory sees agency as exclusively a property of humans, whereas the principle of general symmetry in actor network theory implies that machines may also be agents. Drawing on critiques of both structuration theory and actor network theory, this paper develops a theoretical account of the interaction between human and machine agency: the double dance of agency. The account seeks to contribute to theorisation of the relationship between technology and organisation by recognizing both the different character of human and machine agency, and the emergent properties of their interplay.

Quality loss in prawns due to double freezing

Icing is the practice for preserving prawns on board fishing boats in India. Majority of these boats need to preserve the catch only for a few hours because of the short duration of the fishing trip. However, with the anticipated introduction of a considerable number of bigger fishing vessels which can remain in the fishing ground for longer periods, more than fortnight, preservation methods, other than icing are required to retain prime quality. Freezing and cold storage of whole prawns on board followed by thawing and processing on land is a possible proposition. The extent of quality loss in prawns during these operations is one of the important points to be considered. Hence, laboratory scale studies were undertaken on double freezing of prawns and the results are dealt within this communication.

Preliminary observations in the design and operation of a three panel, double trawl net

Fishing operations were conducted off Kakinada using a 3 panel double trawl net with twin cod-ends to study the utility of the net in catching both bottom and off bottom fishes. The observations indicate that the net is effective in simultaneous catching of bottom as well as off-bottom fishes and separating them while in operation. The design details of the net and the particulars of the fishing operations conducted are presented.

Double-rig shrimp trawling, its rigging, comparative efficiency and economics

A radical and revolutionary change from the hitherto employed shrimp trawling is reported for better productivity and economy in deep sea trawling with medium and large vessels. Studies carried out off Veraval with a 13.7 m. four seam shrimp trawl as conventional single-rig and two 6.8 m four seam shrimp trawls as double-rig from a 15.2 m fishing vessel showed an increase of 98% shrimp catch by double-rig over single-rig at 86.3 % of the power utilised by the latter. It has also been worked out, theoretically, how better this available power can be utilised for further improvement of catch. An increase of 15% head rope length in case of double-rig over the optimum single-rig gear of any vessel is recommended.

Observations on the artificial fertilization of eggs and larval rearing of the grey mullet, Mugil cephalus L.

The results are presented of attempts to artificially fertilize Mugil cephalus eggs in the Philippines. Embryonic development is outlined and rearing of the larvae described. Mass mortality occurred during week 3 of rearing.

A comparative study on the induced breeding and in vitro fertilization performance by various inducing agents in catfish, Heteropneustes fossilis (Bloch)

Brood catfish, Heteropneustes fossilis were collected from Tamirabarani river basin of Tamil Nadu, India and kept in cement tanks. Three inducing hormones viz, Ovaprim, Ovatide and WOVA-FH were injected at the rate of 0.5, 1.0, 1.5 and 2.0 ml/kg body weight in order to induce oocyte maturation and ovulation. After 10-13h of injection at a water temperature of 27±-0.5°C, stripping of eggs and in vitro fertilization was done. Ovaprim gave maximum (94.67%) hatching rate followed by Ovatide (90.33%) and WOVA-FH (77.33%).

Effects of exogenous double-stranded RNA on the basonuclin gene expression in mouse oocytes

In plants and less-advanced animal species, such as C.elegans, introduction of exogenous double-stranded RNA (dsRNA) into cells would trigger degradation of the mRNA with homologous sequence and interfere with the endogenous gene expression. It might represent an ancient anti-virus response which could prevent the mutation in the genome that was caused by virus infection or mobile DNA elements insertion. This phenomenon was named RNA interference, or RNAi. In this study, RNAi was used to investigate the function of basonuclin gene during oogenesis. Microinjection of dsRNA directed towards basonuclin into mouse germinal-vesicle-intact (GV) oocytes brought down the abundance of the cognate mRNA effectively in a time- and concentration-dependent manner. This reduction effect was sequence-specific and showed no negative effect on other non-homologous gene expression in oocytes, which indicated that dsRNA can recognize and cause the degradation of the transcriptional products of endogenous basonuclin gene in a sequence-specific manner. Immunofluorescence results showed that RNAi could reduce the concentration of basonuclin protein to some extent, but the effect was less efficient than the dsRNA targeting towards tPA and cMos which was also expressed in oocytes. This result might be due to the long half life of basonuclin protein in oocytes and the short reaction time which was posed by the limited life span of GV oocytes cultured in vitro. In summary, dsRNA could inhibit the expression of the cognate gene in oocytes at both mRNA and protein levels. The effect was similar to Knock-out technique which was based on homologous recombination. Furthermore, hairpin-style dsRNA targeting basonuclin gene could be produced by transcription from a recombinant plasmid and worked efficiently to deplete the cognate mRNA in oocytes. This finding offered a new way to study the function of basonuclin in the early stage of oogenesis by infection of primordial oocytes with the plasmid expressing hairpin-style basonuclin dsRNA.