1,897 research outputs found

    Ontogenia larval comparativa de duas esp?cies (Characiformes e Siluriformes) end?micas do rio S?o Francisco

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    Objetivou-se com este trabalho comparar histologicamente o desenvolvimento ontogen?tico de duas esp?cies de peixes end?micos da bacia do rio S?o Francisco, Prochilodus argenteus (curimat?-pacu) e Lophiosilurus alexandri (pacam?). As coletas para as an?lises histol?gicas foram realizadas a cada 24 horas a partir do momento da eclos?o at? o 14? dia p?s-eclos?o (DPE) para a observa??o do desenvolvimento larval e at? o 39? DPE para a observa??o do desenvolvimento gonadal. As larvas foram fixadas inteiras em solu??o de Bouin e as l?minas histol?gicas foram coradas pelo m?todo de Hematoxilina-Eosina. Larvas de pacam? exibiram um tamanho corporal maior em rela??o ?s larvas de curimat?-pacu desde a eclos?o. Larvas de pacam? apresentaram a abertura da boca e in?cio da pigmenta??o dos olhos no momento da eclos?o, enquanto que nas larvas de curimat?-pacu, esses eventos foram observados no 1? DPE. No curimat?-pacu a visualiza??o e a insufla??o da bexiga natat?ria ocorreram no 1? e 3? DPE, respectivamente, sendo esses eventos mais tardios no pacam?, com visualiza??o no 2? e insufla??o no 8? DPE. Os gr?nulos de vitelo foram absorvidos no 4? DPE pelo curimat?-pacu e no 10? DPE pelo pacam?. No 7? DPE, o tubo digest?rio do pacam? apresentou-se mais diferenciado em rela??o ao curimat?-pacu. O sistema digest?rio de ambas as esp?cies ao 14? DPE demonstraram caracter?sticas relacionadas aos seus respectivos h?bitos alimentares, com est?mago amplo e intestino curto no pacam?, t?picos de h?bito carn?voro; est?mago com fun??o mec?nica e intestino longo no curimat?-pacu, t?picos de h?bito detrit?voro. O tecido epitelial de revestimento, formado por uma ?nica camada de c?lulas nas larvas rec?m-eclodidas (0 DPE), apresentou diferencia??o ao longo dos dias, exibindo presen?a de escamas no curimat?-pacu e numerosas c?lulas ?club? na regi?o epitelial intermedi?ria do pacam?, em avalia??es realizadas ao 39? DPE. Analisando os indiv?duos com 39 DPE, verificou-se a presen?a de g?nadas indiferenciadas com c?lulas som?ticas e c?lulas germinativas primordiais que foram observadas realizando migra??o no sentido caudo-cranial desde o 1? DPE em ambas as esp?cies. P?de-se concluir que as altera??es anat?micas observadas durante a ontogenia de larvas P. argenteus e L. alexandri est?o diretamente relacionadas ao h?bito alimentar e ao comportamento inerente ? cada esp?cie, sendo uma detrit?vora que nada ativamente na coluna d??gua, e outra carn?vora que habita regi?es de fundo, respectivamente. Aos 39 dias p?s-eclos?o, em ambas as esp?cies n?o foram observados ind?cios histol?gicos de diferencia??o sexual.Banco do Nordeste do Brasil (BNB)Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq)Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016.The objective of this work was to compare histologically the ontogenetic development of two endemic species of fish from the S?o Francisco river basin, Prochilodus argenteus (curimat?-pacu) and Lophiosilurus alexandri (pacam?). The samples for the histological analyzes were performed every 24 hours since the moment of hatching until the 14th day post-hatching (DPH) for observation of the larval development and until the 39th DPH for the observation of gonadal development. The whole larvae were fixed in Bouin's solution and the histological slides were stained by the Hematoxylin-Eosin method. Pacam? larvae exhibited a larger body size relative than the curimat?-pacu larvae since hatching. Pacam? larvae presented the mouth opening and pigmentation of eyes beginning at the time of hatching, whereas in curimat?-pacu larvae, these events were observed in the 1st DPH. The visualization and the inflation of the swim bladder in the curimat?-pacu, occurred in the 1st and 3rd DPH, respectively, being these events in the pacam? later, with visualization in the 2nd and insufflation in the 8th DPH. The yolk granules were absorbed in the 4th DPH by the curimat?-pacu and in the 10th DPE by the pacam?. In the 7th DPH, the pacam??s digestive tube was more differentiated than curimat?-pacu. The digestive system of both species at the 14th DPH has features of it eating habits the pacam?, with a broad stomach and a short intestine in the pacam?, typical of a carnivorous habit; stomach with a mechanical function and a long intestine in curimat?-pacu, typical of detritivorous habit. The epithelial lining tissue, formed by a single layer of cells in the newly hatched larvae (0 DPH), showed a differentiation throughout the days, exhibiting scales in curimat?-pacu and numerous club cells in the middle epithelial region of the pacam?, at evaluations carried at the 39th DPH. Analyzing the individuals with 39 DPH, the presence of undifferentiated gonads with somatic cells and primordial germinative cells were observed, which has a caudate-cranial migration since 1st DPH in both species. It was concluded that the anatomical alterations of the ontogeny of P. argenteus and L. alexandri larvae are directly associated to the feeding habit and the inherent behavior of each species, being these detritivorous that nothing actively in the column of water and carnivorous that inhabits bottom regions, respcectively. At the 39 day post-hatching, both species hasn't evidenced of sexual differentiation

    Effects of 8-week online, supervised high-intensity interval training on the parameters related to the anaerobic threshold, body weight, and body composition during pregnancy: a randomized controlled trial

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    We aimed to assess the effects of an 8-week, online high-intensity interval training (HIIT) program on the parameters related to the anaerobic threshold (AT), body weight, and body compo sition in pregnant women. A total of 69 Caucasian women with an uncomplicated singleton preg nancy (age: 31 ± 4 years; gestational age: 22 ± 5 weeks; mean ± standard deviation) were randomly allocated to either an 8-week HIIT program (HIIT group) or to a comparative 8-week educational program (EDU group). Our most important finding was that even with the 8-week progression of pregnancy and physiological weight gain, the HIIT group maintained the same level of parameters related to AT: volume of oxygen at the AT (VO2/AT), percentage of maximal oxygen uptake at the AT (%VO2max/AT), and heart rate at the AT (HR/AT). In contrast, in the EDU group we observed a substantial deterioration of parameters related to the AT. The HIIT intervention substantially re duced the fat mass percentage (median: 30 to 28%; p < 0.01) and improved the total fat-free mass percentage (median: 70% to 72%; p < 0.01). In the EDU group, the body composition did not change significantly. An online, supervised HIIT program may be used to prevent the pregnancy-related risk of excessive weight gain and reduction in exercise capacity without yielding adverse obstetric or neonatal outcomes.info:eu-repo/semantics/publishedVersio

    Enzymatic and biochemical characterization of Bungarus sindanus snake venom acetylcholinesterase

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    This study analyses venom from the elapid krait snake Bungarus sindanus, which contains a high level of acetylcholinesterase (AChE) activity. The enzyme showed optimum activity at alkaline pH (8.5) and 45ºC. Krait venom AChE was inhibited by substrate. Inhibition was significantly reduced by using a high ionic strength buffer; low ionic strength buffer (10 mM PO4 pH 7.5) inhibited the enzyme by 1. 5mM AcSCh, while high ionic strength buffer (62 mM PO4 pH 7.5) inhibited it by 1 mM AcSCh. Venom acetylcholinesterase was also found to be thermally stable at 45ºC; it only lost 5% of its activity after incubation at 45ºC for 40 minutes. The Michaelis-Menten constant (Km) for acetylthiocholine iodide hydrolysis was found to be 0.068 mM. Krait venom acetylcholinesterase was also inhibited by ZnCl2, CdCl2, and HgCl2 in a concentrationdependent manner. Due to the elevated levels of AChE with high catalytic activity and because it is more stable than any other sources, Bungarus sindanus venom is highly valuable for biochemical studies of this enzyme

    Phase diagram for non-axisymmetric plasma balls

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    Plasma balls and rings emerge as fluid holographic duals of black holes and black rings in the hydrodynamic/gravity correspondence for the Scherk-Schwarz AdS system. Recently, plasma balls spinning above a critical rotation were found to be unstable against m-lobed perturbations. In the phase diagram of stationary solutions the threshold of the instability signals a bifurcation to a new phase of non-axisymmetric configurations. We find explicitly this family of solutions and represent them in the phase diagram. We discuss the implications of our results for the gravitational system. Rotating non-axisymmetric black holes necessarily radiate gravitational waves. We thus emphasize that it would be important, albeit possibly out of present reach, to have a better understanding of the hydrodynamic description of gravitational waves and of the gravitational interaction between two bodies. We also argue that it might well be that a non-axisymmetric m-lobed instability is also present in Myers-Perry black holes for rotations below the recently found ultraspinning instability.Comment: 1+22 pages, 3 figures. v2: minor corrections and improvements, matches published versio
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