Triploidy induction in Heterobranchus longifilis (Family: Clariidae) by cold shock

Triploid was induced in African Catfish (Heterobranchus longifilis) by cold shocking activated eggs at 5 degree C for forty minutes starting 3-4 minutes after fertilization. Triploidy was confirmed from mitotic chromosomes prepared from embryo which showed 100% triploidy in the cold shocking treatment and 100% diploidy in the control treatment

Effects of some environmental factors on the fecundity of Tilapia species (Family Cichlidae) in Kigera Reservoir, New Bussa

The effects of some environmental factors on the fecundity of Tilapia species (Family Cichilidae) was carried out at the Kigera dam. Four Tilapia species caught were Tilapia zilli, Hemichromis fasciatus, Sarotherodon galilaeus and Oreochromis niloticus while the environmental factors considered were water temperature, Dissolved Oxygen, pH value, level of rainfall and rate of sunshine and range of time. 43 fish comprising of 25 male with (58.1%) and 18 females having (41.9%) were studied with 74.42% been sexually matured. Both high levels of rainfall and dissolved oxygen favoured fecundity. The spawning peak occurred in (July), environmental factors monitored indicated that dissolved oxygen ranges from 3.7 to 4.45mg/lit rainfall ranges from (34.90mm to 237.80mm) sunshine ranges from (5hrs-8hrs) and pH ranges from (7.35-7.45). The spawning of these species in their natural or hatchery condition is therefore best achieved during the peak of raining season

Expression of eph-family receptor tyrosine kinases and ephrins in the tadpole of the frog Xenopus laevis, and possible roles in the development of retinotectal topography

Assembling a nervous system requires exquisite specificity in the construction of neuronal connectivity. One method by which such specificity is implemented is the presence of chemical cues within the tissues, differentiating one region from another, and the presence of receptors for those cues on the surface of neurons and their axons that are navigating within this cellular environment.

Connections from one part of the nervous system to another often take the form of a topographic mapping. One widely studied model system that involves such a mapping is the vertebrate retinotectal projection-the set of connections between the eye and the optic tectum of the midbrain, which is the primary visual center in non-mammals and is homologous to the superior colliculus in mammals. In this projection the two-dimensional surface of the retina is mapped smoothly onto the two-dimensional surface of the tectum, such that light from neighboring points in visual space excites neighboring cells in the brain. This mapping is implemented at least in part via differential chemical cues in different regions of the tectum.

The Eph family of receptor tyrosine kinases and their cell-surface ligands, the ephrins, have been implicated in a wide variety of processes, generally involving cellular movement in response to extracellular cues. In particular, they possess expression patterns-i.e., complementary gradients of receptor in retina and ligand in tectum- and in vitro and in vivo activities and phenotypes-i.e., repulsive guidance of axons and defective mapping in mutants, respectively-consistent with the long-sought retinotectal chemical mapping cues.

The tadpole of Xenopus laevis, the South African clawed frog, is advantageous for in vivo retinotectal studies because of its transparency and manipulability. However, neither the expression patterns nor the retinotectal roles of these proteins have been well characterized in this system. We report here comprehensive descriptions in swimming stage tadpoles of the messenger RNA expression patterns of eleven known Xenopus Eph and ephrin genes, including xephrin-A3, which is novel, and xEphB2, whose expression pattern has not previously been published in detail. We also report the results of in vivo protein injection perturbation studies on Xenopus retinotectal topography, which were negative, and of in vitro axonal guidance assays, which suggest a previously unrecognized attractive activity of ephrins at low concentrations on retinal ganglion cell axons. This raises the possibility that these axons find their correct targets in part by seeking out a preferred concentration of ligands appropriate to their individual receptor expression levels, rather than by being repelled to greater or lesser degrees by the ephrins but attracted by some as-yet-unknown cue(s).

Structure of the limbs and its significance for the ecology and systematics of the family Chydoridae. [Translation of: Voprosy Gidrobiologii, p385, 1965]

For an explanation of the dynamics of numbers of chydorids, appearing a massive group in the littoral of fresh water bodies, the structure of the limbs of 29 species was studied.

Variações sobre liberdade: estudo do conceito de liberdade no pensamento metafísico de Descartes

O objetivo desta dissertação é examinar alguns aspectos da doutrina da liberdade humana no pensamento metafísico de Descartes. Através do exame do conceito cartesiano da liberdade humana nas Meditações, nos Princípios e na correspondência com Mesland, pretende-se averiguar se Descartes modifica esse conceito ao longo de sua obra e, por conseguinte, se é possível ou não aceitar a tese da evolução deste conceito. A abordagem de tal questão leva em conta, além da análise dos textos de Descartes, as interpretações mais representativas sobre o assunto.

Key to the larvae of the genera of the sub-family Orthocladiinae from Larvae and Pupae of midges of the sub-family Orthocladiinae of the fauna of the USSR. [Translation from: Larvae and pupae of midges of the subfamily Orthocladiinae of the fauna of the USSR (Diptera, Chironomidae = Tendipedidae) (ed. Pankratova V.Ya.), 51-55. Leningrad, Nauka, 1970. ]

A key to the larvae of the genera of the sub-family Orthocladiinae from Larvae and Pupae of midges of the sub-family Orthocladiinae. Parts of the key refer to the rest of the publication which is not included in this partial translation.

Family: Cladophora Kutzing 1843. identification key. [ Translation from: Flora Slodkowodna Polski 10, 227-263, 1972.]

A description of the algal genus Cladophora from Vol 10 of the ”Freshwater Flora of Poland”. Illustrations are included.

The family of chironomids or midges - Chironomidae. Keys to larvae and pupae [Translation from: Guide to the freshwater invertebrates of the European area of the USSR (Plankton and benthos) (ed. L. A. Kutikova and Ya. I. Starobogatov), p.371-431. Leningrad, Gidrometeoizdat, 1977]

The translation of this section of the larger publication ”Opredelitel' presnovodnykh bespozvonochnykh evropeiskoi chasti SSSR. (Plankton i bentos)” provides identification keys to the larvae and pupae of chironomids that occur in the Soviet Union. The morphology of the larvae of Chironomidae is described in the introductory part.

Diasporization and family relations in Nella Larsens Quicksand and Jamaica Kincaids Lucy: the construction of female identity

O principal objetivo desta dissertação é investigar e analisar como os movimentos diaspóricos e as relações familiares exercem influência na construção das identidades das mulheres em Quicksand, de Nella Larsen, e Lucy, de Jamaica Kincaid. As questões a que pretendo responder são: Como as personagens principais, Helga Crane e Lucy, lidam com as diferentes culturas que encontram nas suas trajetórias ? ; Como essas diferentes culturas lidam com essas mesmas personagens?; e Como o encontro entre essas diferentes culturas e as relações familiares são descritos e influenciam na construção da identidade feminina nessas obras?. Minha hipótese é que encontraremos nas obras selecionadas duas jornadas, portadoras tanto de aspectos comuns quanto distintos, que começam com o desejo das personagens principais de escapar da opressão patriarcal. Isto é, Helga Crane e Lucy passam por um período de muitas descobertas sobre elas mesmas e as sociedades com que têm que lidar, o que determina dois produtos diferentes: a construção das identidades híbridas de Lucy, em meio a sua solidão, na obra de Kincaid, e a construção e o sufocamento das identidades de Helga pela religião, o patriarcado e as relações familiares, na obra de Larsen

Development of larval and early juvenile penpoint gunnel (Apodichthys flavidus) (family: Pholidae)

The penpoint gunnel (Apodichthys flavidus) is a member of the perciform family Pholidae. Pholids, commonly referred to as gunnels, are eel-like fishes that inhabit the rocky intertidal and subtidal regions of the northern oceans and are often associated with macroalgae, such as Fucus spp. or kelp (Watson, 1996). Gunnels are ecologically important forage fishes that form part of the diet of birds and commercially important groundfish species (Hobson and Sealy, 1985; NMFS1; Golet et al., 2000). The diet of A. flavidus and other pholids comprises primarily harpactacoid copepods, gammarid amphipods, isopods, and other crustaceans (Cross, 1981). Apodichthys flavidus ranges along the west coast of North America from southern California to the Gulf of Alaska (Mecklenburg et al., 2002). Adult A. flavidus are distinguished from other pholids by their total vertebral counts, the presence of a thick and grooved first anal spine, a preanal length that is approximately 60% standard length (SL), and a dark green to light olive coloration (Yatsu, 1981). It is one of the largest pholids (up to 46 cm) and is important in the live fish trade for both home and public aquaria (Froese and Pauly2).

A questão do sujeito dos sentimentos no dualismo de Descartes

Tendo como pano de fundo a análise da metafísica do dualismo cartesiano de substâncias, a presente tese tem como objetivo examinar a questão sobre qual seria o sujeito dos predicados que denotam sentimentos nos textos de Descartes. A hipótese proposta é a de que apenas substâncias podem ser consideradas sujeitos últimos de inerência desses predicados. Apesar disso, será argumentado que os homens e animais, embora não sejam substâncias, podem ser considerados sujeitos de atribuição desses predicados, visto que eles possuem uma unidade especial, a saber, uma unidade de composição, que assegura tal atribuição. Para tanto, a tese será desenvolvida em três eixos principais. Partindo do exame da teoria cartesiana da substância e de suas definições, analisarei o conceito de substância extensa, levando em conta o debate existente entre as interpretações monistas e pluralistas deste conceito. Neste contexto, discutirei a especificidade do corpo humano em relação aos demais corpos da natureza, considerando alguns aspectos da teoria cartesiana dos animais-máquinas. Em seguida, tratarei da questão da unidade do homem, bem como de outros tipos de unidade reconhecidos por Descartes. Por fim, examinarei a teoria cartesiana da causalidade com o propósito de determinar quais teorias da causalidade, interacionista ou ocasionalista, na visão de Descartes, poderiam servir como modelos explicativos dos sentimentos humanos e dos sentimentos animais. A hipótese a ser defendida nesta tese está em consonância com a visão de que a teoria cartesiana das três noções primitivas particulares, a saber, pensamento, extensão e união, é plenamente compatível com o dualismo metafísico de substâncias que Descartes propõe e, portanto, não implica um enfraquecimento deste último.