1,721,563 research outputs found
Successful inoculation of Artemia and production of cysts in man-made salterns in the Philippines
No full textALSO IN: Quarterly Research Report / SEAFDEC. Aquaculture Department, 3(1):19-20 1979.The objective of the inoculation described in this paper was to test the feasibility of culturing Artemia in man-made earthen salterns and of producing adults and cysts for use in aquaculture projects in the Philippines. San Francisco Bay (California, USA) Artemia were inoculated in two concrete tanks and in four earthen ponds which are part of a small local salt factory.
It was found that Artemia can be grown (with continuous production of nauplii and cysts) year-round in covered concrete tanks and in open concrete tanks and earthen ponds during the dry season (February to June). Lethal effects of too high water temperatures (>35°C) to the cultures were anticipated by the use of green coconut fronds placed on the water surface alongside the walls of the tanks and the earthen dikes.
Rice bran enriched with vitamins and traces of minerals appeared to be a good food for Artemia cultured in aerated concrete tanks; in the earthen salt ponds the brine shrimp grew well on the natural food present.
Over a 3 month production period, 26 kg dry weight cysts and 150 kg live weight adults have been harvested from a total surface of 1.7 ha of salt ponds and brine tanks
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Priming the immune system of Litopenaeus vannamei with bacterial heat shock protein 70 homologue DnaK against Vibrio campbellii and white spot syndrome virus (WSSV) infection
Full text linkDisease outbreaks are considered to be the main constraint to aquaculture development. The disadvantages of widespread use of antibiotics have been realized in whole animal production industry including aquaculture. Thus there is increasing demand for developing alternative disease control strategies. The heat shock protein 70 (HSP70) were discovered as a potential candidate for the development of a new disease control approach.
This thesis evaluates a novel anti-‐infective strategy to control vibriosis and WSSV in aquaculture. More specifically, investigations were performed to elucidate the role of recombinant heat shock protein 70 (Hsp 70), derived from a prokaryotic source, in generating an immune response and to instigate protection against pathogenic Vibrio campbellii and White Spot Syndrome virus (WSSV).
Firstly, the role of bacterial HSP70 (DnaK) as an efficient immuno-stimulant in L. vannamei was verified by including a chemically synthetic, microbial contaminants free DnaK fragment peptide (DnaK442-‐491) as control.
Secondly, in order to evaluate the acute immune stimulatory effect of DnaK in L. vannamei, regulation of four important immune-‐related gene groups (prophenoloxidase, transglutaminase, penadins, endogenous HSP70) were monitored 12h after DnaK intramuscular injection.
Significantly responding genes were selected as immune markers for subsequent study.
Subsequently, the priming effect of bacterial HSP70 DnaK against V. campbellii and WSSV infection was evaluated. Thesis demonstrated that pre-‐treatment of L. vannamei with the DnaK, followed by a non-lethal V. campbellii challenge affected the transcription of 3 immune marker genes, TGase-‐1, proPO-‐2 and lvHSP70.
Similarly, we tested the hypothesis that DnaK can prime the immune system of L.vannamei to cope with a viral infection (WSSV). Transcriptions of two immune related genes, TGase-‐1 and proPO-‐2, were quantified within 12 hpp. Strong synergistic effects induced by both DnaK and WSSV on TGase-‐1 and proPO-‐2 were exhibited.
In conclusion, the results presented in this thesis indicate a possible role for DnaK as an immune priming agent in L. vannamei against V. campbellii and WSSV infections
Experimenten op het effect van temperatuur op white spot syndrome virus infectie in Litopenaeus vannamei garnalen
Full text linkDissertação de mest., Aquacultura e Pescas, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2006White Spot Disease (WSD) is an aggressive and devastating viral disease caused by the White Spot Syndrome Virus (WSSV). This highly pathogenic and widespread disease, present throughout Asia and the Americas, can cause up to 100% mortality within 3-7 days after infection. It is annually responsible for huge ecological and economical losses in the main producing countries and forms as such one of the greatest threats for the further sustainable development of shrimp aquaculture.
Previous research showed that manipulation of physical factors gave promising results: manipulation of the environmental factors such as temperature produced the most interesting and promising results. For this thesis three experiments were performed, all in which pacific white shrimp (Litopenaeus vannamei) were intramuscularly inoculated with a well-defined viral dose (30 and/or 10000 SID50) and exposed to high water temperature via standardised protocols. The first experiment looked at the efficacy of elevated temperature for protecting shrimp against WSSV. Practically, four temperature treatments in which an elevated temperature (33 °C) was either applied before virus inoculation, after the inoculation, both before and after inoculation, and in the fourth treatment a low temperature (27ºC) was used throughout the test. In the second series of experiments the protective value of high temperature after an initial period of viral replication was evaluated. Water temperature was raised from 27ºC to 33ºC at 0, 12 or 24 hours post WSSV inoculation. Maintaining and controlling such high water temperatures for longer periods of time is of course very unpractical in field conditions and probably economically unfeasible, so the third experiment evaluated the effectiveness of shorter cyclic exposure periods to high water temperature. Hence, the shrimp were exposed to daily temperature cycles (33ºC/27ºC) with 6, 12 and 18 hours of high water temperature, during five consecutive days.
Experiment 1 demonstrated a total blocking of disease progression when hyperthermia was applied immediately post inoculation. The protection was very effective even with a high viral dose (10000 SID50). The second experiment, at a low viral dose (30 SID50), showed that high temperature to some extent also worked therapeutic in that previously 24 hours of virus replication could be allowed. At a high infection dose (10000 SID50) the level of protection was however not so effective. In Experiment 3, only a minimum of 18 hours at 33°C resulted in a significant lower I
mortality with the infected shrimp. The results from all the experiments clearly show the potential of high water temperature for preventing mortality in WSSV infected shrimp
Artemia biodiversity in Central and Eastern Asia
No full textThe brine shrimp Artemia is a small crustacean occurring worldwide in hypersaline biotopes. Its cysts, produced in stressful environmental conditions, can be stored for several years; the emerging larva is a convenient substitute for the natural plankton diet of fish and shrimp larvae and is an indispensable live food item in marine finfish and shellfish hatchery operations worldwide, thanks to its availability, nutritional quality, and easy use. According to present knowledge the genus Artemia groups a few bisexual species and numerous parthenogenetic forms. This research work contributes to the knowledge of the biodiversity of the genus Artemia in Central and Eastern Asia. Firstly the existing literature on Artemia sites in this area is reviewed, with focus on Southwest Siberia (Russia) and the Qinghai-Tibet Plateau (P.R. China), and anthropogenic threats to Artemia biodiversity in the area are sketched. This work further reports on a field survey conducted in salt lakes in Southwest Siberia and presents data on their topography, abiotic conditions, primary production and Artemia population dynamics. Data are presented on a study of Artemia samples from the Qinghai-Tibet Plateau. Laboratory culture tests showed these samples to contain mixtures of parthenogenetic and bisexual individuals. PCR-RFLP analysis of individual cysts using a 1500 bp mtDNA I fragment and digestion with four restriction endonucleases revealed that the 13 populations analysed could be classified in three distinct groups, each with its characteristic set of haplotypes. This work also presents a study assessing how the original parthenogenetic populations from the Bohai Bay, China, an area with intensive aquaculture activities, has evolved since 1989, using PCR-RFLP analysis These findings are discussed in the light of similar observations elsewhere in the world, and of possible bioconservation measures. Next this work describes tests to assess the usefulness of the PCR-DGGE technique as a tool for rapid and dependable screening of the species/strain composition of an Artemia sample, by analysing both artificial and natural samples of mixed species status. Finally, the overall results of this work are discussed in the framework of its objectives, and in the light of natural or man-generated heterogeneity of Artemia samples, and its repercussions for data interpretation. The importance of the isolation of representative biological study material from nature is emphasized, and the possible implications of analysing cysts or active life stages
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