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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Fungi associated with post-harvest deterioration of dried Clarias gariepinus vended in some markets in Uyo, Akwa Ibom state, Nigeria
No full textMycoflora of dried Clarias gariepinus (Burchell, 1822) were studied on samples obtained from Afaha, Okpokpo and Itam markets in Uyo, Akwa Ibom State using standard methods. Potato dextrose agar was used for isolation process. This was done twice (first and seventh day). Fungi were identified according to their macroscopic and microscopic characteristics. Results revealed that fish samples from okpokpo market contained highest number (10) of fungal isolates while samples from Afaha and Itam markets recorded seven each. Species of Aspergillus, Fusarium, Candida, Epicoccum, Rhizopus, Absidia, Penicillium, Trichoderma, Mucor, Cladosporium and Alternaria were isolated. The most commonly isolated fungi were Aspergillus flavus, Aspergillus niger, Fusarium sp. and Rhizopus sp. The least isolated fungi from Afaha market were A. glaucus (10.0% and 13.1%) and Fusaruim sp. (5.5% and 15.3%) while Okpokpo market Penicillium was the least at 13.2% and 22.5% at initial and final isolation respectively. The highest frequencies of occurrence were: Afaha market, Rhizopus sp. (45.4%); Okpokpo market, A. flavus (56.1%) and Itam market, Alternaria sp. at 46.65%. Generally, incidence of A. flavus was highest and samples from Okpokpo market recorded highest frequency of occurrence of fungi at final isolation. This high frequency of occurrence of these fungi revealed reduction in value of dried catfish, subsequent spoilage and increase in economic loss.Key Words: Mycoflora, isolation, fungi, Fusarium, C. gariepinu
Proximate compositions and length-weight relationships of hybrid catfish, Clarias gariepinus (♂) X Heterobranchus bidorsalis (♀) under various densities
No full textThe study evaluated proximate compositions, length-weight relationships, condition factor and the survival rates of hybrid catfish, Clarobranchus (Clarias gariepinus (male) X Heterobranchus bidorsalis (female) reared at different densities in tarpaulin tanks. Fish were stocked at densities of 25, 50, 75 and 100fish/m3. Each treatment was replicated three times. Fish were fed with commercial catfish feed (45% crude protein) at 5% body weight for 84 days. Length and weight data collected were analyzed with FISAT software using the ELEFAN package to estimate relationship in body parameters. The mean exponent (b) for total length was 3.07 for fish reared at 75fish/m3. This showed positive allometric function, indicating that the species gets plumper as it grows larger. The regression line indicated a significant relationship (r = 0.9112; p < 0.05) with the equation W = 5.3783L3.0700. This showed that there was a high and significant correlation between the various total length and weight of Clarobranchus. Fish condition was best at 75fish/m3 density. There were no variations (p<0.05) in fish survival rates and whole body compositions. The results suggested that 75fish/m3 provided optimum environment for rearing Clarobranchus.
Keywords: Hybrid, catfish, condition factor, survival, nutrient value
Influence of processing methods on quality and stability of silver catfish (Chrysichthys nigrodigitatus)
No full textThe study assessed different processing methods (freezing, smoking, oven drying and boiling) on fillet nutritional quality and stability of silver catfish. All analyses followed standard procedure. Results of proximate composition showed significant increase (p< 0.05) in protein (51.98%), lipid (11.65%), ash (3.82%) and calorie (432.57 Kcal/g) contents in the dried fillets. Thus, these variable increased with increasing processing temperature. On the other hand, moisture and carbohydrate contents decreased with temperature. The stability indices showed significant differences (p < 0.05) in free fatty acid of frozen (0.21%), boiled (0.8%), smoked (2.96%) and dried (9.87%). The lowest calcium (39.7%) was recorded in the frozen sample while the highest level (53.12%) in oven dried. Thiobarbituric acid decreased with increase in processing temperature with the highest level (27.14 mg MDA/100g) observed in the frozen fillet while the least value (2.08 mg MDA/100g) was obtained in the boiled samples. Calcium and phosphorus contents did not show any particular trend. The smoked fish fillet had the highest fibre content of 2.6%. Total volatile base nitrogen was generally low in all treatments. Inference from this study revealed that differently processed Chrysichthys nigrodigitatus was a rich source of fatty acids and essential minerals being very vital to the diet of humans
Effects of ethanolic extracts of Ackee apple (Blighia sapida) on biochemical parameters of Clarias gariepinus juveniles
No full textThe influence of ethanolic stem bark extract of Ackee Apple (Blighia sapida) was assessed on hepatic and renal functions in juvenile Clarias gariepinus. Fish were exposed to graded concentrations (1.6, 3.2, 6.4 and 12.8 g/L) of the extract for 21 days. The control group had 0.00g/L extract content. 10 fish were used per treatment and each treatment was replicated three times. Physico-chemical parameters (pH, dissolved oxygen and temperature) were monitored throughout exposure period. At the end of the experiment, blood samples were collected and assessed for some indices of hepatic and renal functions. Results showed that extract at 1.6 g/L did not induce significant (p>0.05) alternation in the serum activities of total protein, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and uric acid when compared with the control. However, at higher extract concentrations the effects increased significantly (p<0.05) with increasing concentrations of extract. The highest effects were observed at 12.8 g/L having total protein of 8.51mmol/L, AST (14.39 mmol/L), ALT (16.99 mmol/L), ALP (66.0 mmol/L), uric acid (0.68 mg/L) and creatinine (20.7mg/L). Conclusively, the extract may be considered safe at lower concentration (1.6 g/L) but may potentiate serious biochemical alteration if continuously applied at 12.8 g/L.Key Words: Ackee apple, toxicity, kidney/liver enzymes, catfis
Helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State, Nigeria
No full textThe study examined helminth parasites of cultured Clarias gariepinus and Tilapia zillii in Uyo, Akwa Ibom State. A total of 60 fish samples (30 each of C.gariepinus and T. zillii) were subjected to parasitological examinations. Results revealed a total of 47(78.33%) fishes infected with various species of parasites: Nematodes (Camallanus polypteri, Paracamallanus cyathopharynx, and Procamallanus laevionchus), Cestodes (Polyonchobothrium torulosus and P. clariae) and Trematodes (Dactylogyrus extensus and Glossiduim pedatum) in decreasing order of abundance. Out of the 60 fish samples examined, 47 were infected with 219 parasites: 142(64.84%) nematodes, 40(18.26%) cestodes and 37(16.89%) trematodes. A total of 159(72.60%) parasites were recovered from C. gariepinus out of which 103(64.78%) were nematodes, 19(18.45%) were cestodes and 37(35.92%) were trematodes. While 60(27.40%) parasites were recovered from T. zilli, of which 39(65.00%) were nematodes and 21(35.00%) cestodes. No trematode was observed in the tilapia. The overall prevalence of parasitic infection was 78.33%. The results of chi square analysis showed that females of both species had significantly higher (P<0.05) prevalence of infection 27(84.4%) than males 20(71.4%). Also, C. gariepinus had higher infection rate of 25(83.33%) when compared to 22(73.33%) recorded in T. zillii.
Key words: fish parasites, aquaculture, prevalence, C. gariepinus, T. zilli
Effects of dietary β-carotene on growth and pigmentation of ornamental carp (koi, Cyprinus carpio L.)
No full textThe study aimed at testing the effects of dietary β-carotene supplementation on growth, feed utilization and pigmentation of koi carp (Cyprinus carpio) fry (mean weight 0.43±0.00g and total length of 1.34±0.00cm). Five levels of carotenoid concentrations (0.00, 0.003, 0.006, 0.008, 0.010g/kg) were employed to formulate a 38.00% protein balanced diet. The diets were designated and referred to as Control, Diet 1, Diet 2, Diet 3 and Diet 4 respectively. Fish were stocked at 10fish/15.6litre capacity aquaria and reared for 12weeks. Fry were fed in triplicates at 5% body weight. The database was analyzed and results revealed a dose dependent percentage weight gain with koi carp treated with the extracts experiencing 667.44±10.48%, 691.47±2.79%, 865.12±16.33% and 854.34±12.42% for Diets 1 to 4 respectively. Proximate analysis of fish flesh revealed no significant differences (p<0.05) between treatments in all the parameters. Astaxanthin dominated the body of koi carp, regardless of the concentrations of dietary β-carotene included in the diets. Survival rates were generally high and was not particularly dependent on carotenoid inclusion level. Inference from the study showed that β-carotene at 0.003g/kg to 0.010g/kg inclusion in the diets resulted in increased food conversion, mean weight gain, specific growth rate and protein efficiency ratio.
Keywords: β-carotene, growth, survival, feed utilization, koi carp
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