1,721,003 research outputs found
Degeneration of the olfactory epithelium in the Anguilid eels by hormone treatment
No full textWhile the olfactory cue hypothesis has been proposed for spawning migration of silver eels, it has been shown that olfactory cells and associated mucus cells degenerate in male and female eels after hormonally induced sexual maturation. However, the degeneration of the olfactory organ could be a real event in the sequence of maturation, or may be an unnatural side effect of the hormone treatment itself. We morphologically and histologically examined the olfactory rosettes of hormone-untreated and hormone-treated (mixture of hCG and PG) giant mottled eel (Anguilla marmorata) and Japanese eel (A. japonica). The olfactory rosette from all the hormone-treated specimens significantly degenerated at various degeneration levels even in sexually immature specimens, indicating the side effect of the hormone-treatment. However, a sexually immature non-hormone treated female A. marmorata (87.4 cm TL, 199.4 g BW, at less advanced maturity) had slightly degenerated olfactory rosette. Further studies should focus on conducting natural degeneration of the olfactory rosette during the sexual maturation in tropical eels
Studies on the enhancement of early larval survival of groupers Epinephelus sp.
Full text link The kelp grouper (Epinephelus bruneus) and tiger grouper (Epinephelus fuscoguttatus) are among the important targeted aquaculture species in temperate and tropical water respectively in the Asian region. Nevertheless, reliable of large-scale production of both groupers is greatly hindered by the high mortality at early larval stage. It was reported that larval survival rates for the kelp grouper and tiger grouper were only 0.3-37.0% and 0.02-4.0%, respectively. Therefore, two independent approaches were introduced in this study for the enhancement of early larval survival of both groupers.application/pdfdepartmental bulletin pape
The effects of long jack, Eurycoma longifolia on sperm quality and quantity of African catfish, Clarias gariepinus
Full text linkThe experiment was to study the effects of long jack, Eurycoma longifolia through the sperm quality and quantity of African catfish, Clarias gariepinus. Mostly farmers are using hormone to induce the reproduction in these fishes especially C. gariepinus. For expanding interest in C. gariepinus, there was expanded exertion in the improvement of method for production of fish in hatchery. Thus, the present study was an alternative to improve the production of C. gariepinus. In the present study, two diets with crude protein of 40 % were formulated with different supplementation levels of E. longifolia powder; with no supplementation of E. longifolia (LJ0) and the supplementation of 5 % E. longifolia (LJ5). Eight males of C. gariepinus were randomly distributed into two fibre tanks (2×2×1.5 m) with four fish per tank. The tank was contained green water (pH≈ 7.2, dissolved oxygen≈ 5.3 mg/L, temperature≈ 27.20°C). C. gariepinus were fed at 3% of body weight twice a day for a period of 30 days. The diet in LJ5 had significantly higher in sperm counts (12085.33±286.71x104 sperm/ml), milt volume (0.38±0.04 ml) and motility duration (24.11±0.96sec). While the result for diet in LJ0 in sperm count, milt volune and motility duration were 10014.67±273.76x104sperm/mL, 0.21±0.06 ml and 12.67±0.58sec. However, significant differences were not observed in the body weight gained, total length, specific growth rate and feed conversion ratio (FCR) among the two treatments. Besides, the results were showed E. longifolia possess promising pro-fertility which can be exploited in fish seeds production and 50 g/kg of E. longifolia based diet could give satisfactory and efficient result on the sperm quality and quantity of C. gariepinus
Eggs, larval morphology development and behavioral changes of jade perch (scortum barcoo) larvae
No full textThis study examined the embryonic development of Jade perch (Scortum barcoo) during the early larval stage, emphasizing morphology, sensory organ development, and behavioral changes. Artificial reproduction was conducted using one mature female (1.0 ± 0.0 kg) and two mature males (1.0 ± 0.8 kg) through hormone-induced spawning. The fertilization and hatching rates were recorded as 83.4 ± 0.45％ and 86.4 ± 0.78% respectively, and fertilized egg size was 2.73 ± 0.3 mm. Hatching occurred at 20:20 hours after fertilization (hAF) under 27.3 ± 0.7 ℃ and the size of newly hatched larvae was 2.79 ± 0.05 mm, growing up to 4.73 ± 0.07 mm by 90 hours after hatching (hAH). Morphological developments were observed as follows: eye and fin formation at 6 hAH, noticeable pigmentation at 30 hAH, mouth opening at 36 hAH, jaw movement at 42 hAH, and anus opening at 60 hAH. Sensory organs development was observed as follows: lens formation and inner ear formation at 6 hAH, eye pigmentation and olfactory pit formation at 30 hAH. Behavioral changes were observed as follows: onset of vertical swimming at 12 hAH, onset of horizontal swimming at 18 hAH, with larvae showing positive phototaxis and rheotaxis at 30 hAH, and first feeding starting at 72 hAH. This study concludes that Jade perch undergoes normal development, and these primary data can be used to establish a rearing protocol to further enhance the overall growth performance in captivity
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
