8,129 research outputs found

    Redescription of Hypoptopoma inexspectata (Holmberg, 1883), with notes on its anatomy (Siluriformes: Loricariidae).

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    Hypoptopoma inexspectata is diagnosed and redescribed based on the examination of additional material and comparison with its congeners. This poorly known hypoptopomine species is distributed in the Paraguay and Paraná river draínages. Hypoptopoma inexspectata is diagnosable based on the autapomorphy biserial arrangement of anterior snout rostral margin odontodes, laterally extended to limit between second and third infraorbital plates, with dorsally directed dorsad series separated from ventrally directed ventrad series by a narrow odontode-free area, which at the level of first and second infraorbital plates is reduced to a dividing line of the series. The species can be further distinguished by the combination (1) low number of canal-bearing lateral plates (20-22, typically 21), (2) presence of a shield of prepectoral dermal plates, (3) arrangement of abdominal plates in one paired series of 3-5 plates, (4) shorter least interorbital distance 4856% head lengh, (5) larger horizontal eye diameter 17-20% head lengh, and (6) least orbit-nare distance 812% head lengh. Intraspecific variation skull dermal bones, neuracranium and suspensorium bones, dermal plates, adipose fin is reported. (PDF has 20 pages.

    Value’s of Mathematics Education and Citizenship Education

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    Currently, the Indonesian plane of life is miserable, inparticular on behavior. It is shown by the mushrooming acts of corruption, bribery, anarchy, public deceiving, traffic incompliance, etc. This mean any problem in nation character. The nation character building is the duty of citizenship education. The mission of citizenship education in Indonesian is develop or build the nation character as the instructional effects and nurturant effects. Whereas, another courses include mathematics course have to develop the nation characters through the nurturent effect of the instructional. This paper discussed about the relationship between values of mathematics education and characters contained in Citizenship Education. Key word: value, character, mathematics, citizenshi

    'Parkawala' fishery for catfish at Versova, Mumbai

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    Dol is in important gear employed to exploit catfishes at Versova.The introduction of a small gill net piece locally called 'Parkawala'is tied around the cod end of dol net to exploit catfishes in addition to regular catch of this gear.This net was found to be effective to catch bigger catfishes

    Protein and energy utilisation in two Mekong catfishes, Pangasius Bocourti and Pangasius hypophthalmus

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    Fish unlike terrestrial animal, use a large amount of protein as an energy source for their energy metabolism. When fed on a high protein ration, the fish itself may choose which amount of protein in food will be converted into body growth and which will be burned through the catabolism. Therefore, in the study one diet was designed with a high protein content and fed to fish with different levels: 0, 5, 15,25, 35 and 45g crude protein kg'l.d". P. bocourti has a higher growth rate than P. hypophthalmus at the same food intake. However, the higher growth observed in P. bocourti is obviously associated to higher fat accumulation in the body. The protein efficiency, NPU and PER, tends to bereduced at higher protein intake in both species. Energy and protein requirements for maintenance were calculated to be 128 and 92 kl.kg'l.day", and 5.16 and 3.24 g.kg'l.day", in P. bocourti and P. hypophthalmus, respectively. P. bocourti has nearly a double protein and energy requirement for maintenance. The event may be linked to the fact that P. bocourti has higher growth rate and higher ability to synthesise a large amount of body lipid than P. hypophthalmus. An estimate of protein requirement was in range of 12-13 and 11-12 g.kg'l.day" in P. bocourti and P. hypophthalmus, respectively. The DPIDE ratio was estimated to be 18 and 17 mg.kl" in P. bocourti and P. hypophthalmus, respectively. These low DPIDE ratios may be related to the fact that the protein requirement was relatively low in the two species

    Pectoral sound generation in the blue catfish Ictalurus furcatus

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    Catfishes produce pectoral stridulatory sounds by “jerk” movements that rub ridges on the dorsal process against the cleithrum. We recorded sound synchronized with high-speed video to investigate the hypothesis that blue catfish Ictalurus furcatus produce sounds by a slip–stick mechanism, previously described only in invertebrates. Blue catfish produce a variably paced series of sound pulses during abduction sweeps (pulsers) although some individuals (sliders) form longer duration sound units (slides) interspersed with pulses. Typical pulser sounds are evoked by short 1–2 ms movements with a rotation of 2°–3°. Jerks excite sounds that increase in amplitude after motion stops, suggesting constructive interference, which decays before the next jerk. Longer contact of the ridges produces a more steady-state sound in slides. Pulse pattern during stridulation is determined by pauses without movement: the spine moves during about 14 % of the abduction sweep in pulsers (~45 % in sliders) although movement appears continuous to the human eye. Spine rotation parameters do not predict pulse amplitude, but amplitude correlates with pause duration suggesting that force between the dorsal process and cleithrum increases with longer pauses. Sound production, stimulated by a series of rapid movements that set the pectoral girdle into resonance, is caused by a slip–stick mechanism

    Preliminary studies of the dual role of cotton-seed cake as fish feed and fish pond fertilizer in aquaculture

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    Many locally available fish feeds have been tried in fish culture. These include guinea corn, soya bean, groundnut cake and rice bran. Cotton seed cake has been successfully used as a fishpond organic fertilizer at Ado-Ekiti Government fish farm. Three fishponds stocked respectively with common carps, Heterotis, Tilapia spp., Clarias lazera and Heterobranchus were fed with cotton seed cake. Carps, Tilapia and Heterotis increased rapidly in weight and length while the catifishes did not gro

    A case of intersex occurrence in Steindachneridion parahybae (Steindachner, 1877) (Siluriformes: Pimelodidae) under captivity condition: A cytogenetic and morphological study

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    Poco se sabe sobre la biología reproductiva de Steindachneridion parahybae , una especie de teleósteo gonocorístico en peligro de extinción que habita la cuenca del río Paraíba do Sul y en éste trabajo se describe por primera vez la aparición de individuo intersexo en juvenil de S. parahybae . También se describió el aspecto normal de los ovarios y de los testículos de individuos juveniles procedentes del mismo lote de cría para su comparación; se realizó además el análisis citogenético. Un espécimen fue clasificado a priori como hembra debido a las características macroscópicas de los ovarios, con pequeños oocitos amarillos, sin flecos (característica principal de los bagres macho) y más grande que los testículos; sin embargo el análisis microscópico reveló la presencia de un ovotestis, incluyendo una espermatogénesis completa. S. parahybae presentó un número diploide, 2n = 56 cromosomas, sin evidencia de cromosomas sexuales diferenciados o supernumerarios entre ellos. Estos hallazgos pueden deberse al resultado de la exposición de los individuos a desorganizadores endocrinos o estar influenciados por las condiciones ambientales. Sin embargo no se puede descartar la posibilidad de la presencia de intersexos de forma espontánea. Por lo tanto, la importancia funcional y las consecuencias reproductivas de estas anomalías permanecen aún sin ser determinadas, sugiriendo que esta especie puede ser susceptible a los disruptores endocrinos. Estos resultados contribuyen a ampliar el conocimiento de la biología reproductiva de esta especie en peligro de extinción en condiciones de cautiverio.Little is known about reproductive biology of endangered Steindachneridion parahybae , a gonochoristic teleost species inhabiting the Paraíba do Sul River Basin, and herein is the first description of intersex in S. parahybae juvenile. The normal appearance of ovaries and testes in juvenile from the same lot of breeding were also described for comparison, even as cytogenetic analysis was performed in these juveniles. One specimen was a priori classified as female due to the macroscopic characteristic of ovaries, with small yellow oocytes, without fringes (a main characteristic of catfish male), and larger than testes; however the microscopic analysis revealed the presence of ovotestes, including the complete spermatogenesis. S. parahybae had diploid number, 2n = 56 chromosomes with no evidence of differentiated sex chromosomes or supernumerary chromosomes among them. These findings may be due to the result of exposure to endocrine disrupting compounds or may also be influenced by environmental conditions. The possibility of intersexes might also happen spontaneously and it cannot be ruled out. Therefore, the functional significance and reproductive consequences of this anomaly remain to be determined, suggesting that this species may be susceptible to endocrine disruption. These results contribute to gain expertise about reproductive biology of an endangered species in captivity.Fil: Honji, Renato Massaaki. Universidade de Sao Paulo; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Caneppele, Danilo. Companhia Energética de São Paulo. Unidade de Hidrobiologia e Aquicultura; BrasilFil: Pandolfi, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Lo Nostro, Fabiana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biología Experimental y Aplicada. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Biodiversidad y Biología Experimental y Aplicada; ArgentinaFil: Moreira, Renata G.. Universidade de Sao Paulo; Brasi
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