673 research outputs found

    Experimental rearing of Nile tilapia fry (Oreochromis niloticus) for saltwater culture

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    Represents a preliminary evaluation of the utility of various approaches of early salinity exposure for saltwater culture of tilapias. Studies the reproductive performance of Nile tilapia under laboratory conditions at various salinities; salinity tolerance of progeny; survivorship of fertilized eggs, spawned in freshwater but removed from the mouth of the parent female and artificially incubated at various salinities.Rearing, Experimental culture, Tilapia culture, Salinity tolerance, Salinity effects Oreochromis niloticus

    Salinity tolerance of the tilapias Oreochromis aureus, O. niloticus and an O. mossambicus X O. niloticus hybrid

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    Studies ontogenetic changes in salinity tolerance in tilapias spawned and reared in freshwater using the indices of median lethal salinity, mean survival time and median survival time. Discusses implications of findings for brackish - and seawater culture of tilapias.Salinity tolerance, Hybrids, Tilapia Oreochromis aureus, Oreochromis niloticus, Oreochromis mossambicus

    Understorey plant community and light availability in conifer plantations and natural hardwood forests in Taiwan

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    Questions: What are the effects of replacing mixed species natural forests with Cryptomeria japonica plantations on understorey plant functional and species diversity? What is the role of the understorey light environment in determining understorey diversity and community in the two types of forest? Location: Subtropical northeast Taiwan. Methods: We examined light environments using hemispherical photography, and diversity and composition of understorey plants of a 35‐yr C. japonica plantation and an adjacent natural hardwood forest. Results: Understorey plant species richness was similar in the two forests, but the communities were different; only 18 of the 91 recorded understorey plant species occurred in both forests. Relative abundance of plants among different functional groups differed between the two forests. Relative numbers of shade‐tolerant and shade‐intolerant seedling individuals were also different between the two forest types with only one shade‐intolerant seedling in the plantation compared to 23 seedlings belonging to two species in the natural forest. In the natural forest 11 species of tree seedling were found, while in the plantation only five were found, and the seedling density was only one third of that in the natural forest. Across plots in both forests, understorey plant richness and diversity were negatively correlated with direct sunlight but not indirect sunlight, possibly because direct light plays a more important role in understorey plant growth. Conclusions: We report lower species and functional diversity and higher light availability in a natural hardwood forest than an adjacent 30‐yr C. japonica plantation, possibly due to the increased dominance of shade‐intolerant species associated with higher light availability. To maintain plant diversity, management efforts must be made to prevent localized losses of shade‐adapted understorey plants

    CP and T violation in neutrino oscillations

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    The conditions to induce appreciable CP-and T-odd effects in neutrino oscillations are discussed. The propagation in matter leads to fake CP-and CPT-odd asymmetries, besides a Bohm-Aharonov type modification of the interference pattern. We study the separation of fake and genuine CP violation by means of energy and distance dependence.Comment: To appear in the Proceedings of TAUP 99 Worksho

    Conceitos Atuais No Tratamento Das Ataxias HereditĂĄrias

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    Hereditary ataxias (HA) represents an extensive group of clinically and genetically heterogeneous neurodegenerative diseases, characterized by progressive ataxia combined with extra-cerebellar and multi-systemic involvements, including peripheral neuropathy, pyramidal signs, movement disorders, seizures, and cognitive dysfunction. There is no effective treatment for HA, and management remains supportive and symptomatic. In this review, we will focus on the symptomatic treatment of the main autosomal recessive ataxias, autosomal dominant ataxias, X-linked cerebellar ataxias and mitochondrial ataxias. We describe management for different clinical symptoms, mechanismbased approaches, rehabilitation therapy, disease modifying therapy, future clinical trials and perspectives, genetic counseling and preimplantation genetic diagnosis. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All rights reserved.74324425

    Medium effects for terrestrial and atmospheric neutrino oscillations

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    Matter effects in neutrino propagation translate into effective parameters for the oscillation and fake CP- and CPT-odd quantities, even in a scenario, such as Δ12=0\Delta_{12}=0, where no genuine CP violation is present. This fact seems to impose severe restrictions on the determination of intrinsic parameters of the system from long-baseline experiments. We show, however, that the resonance in the effective mixing ξ~13\tilde{\theta}_{13} can be observed for a certain range of baselines. This provides a way to measure the vacuum mixing angle ξ13\theta_{13} and the sign of Δm232\Delta m_{23}^2 from atmospheric neutrinos, using a detector with energy resolution and charge discrimination.Comment: 13 pages with 5 figure

    The Oscillation Probability of GeV Solar Neutrinos of All Active Species

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    In this paper, I address the oscillation probability of O(GeV) neutrinos of all active flavours produced inside the Sun and detected at the Earth. Flavours other than electron-type neutrinos may be produced, for example, by the annihilation of WIMPs which may be trapped inside the Sun. In the GeV energy regime, matter effects are important both for the ``1-3'' system and the ``1-2'' system, and for different neutrino mass hierarchies. A numerical scan of the multidimensional three-flavour parameter space is performed, ``inspired'' by the current experimental situation. One important result is that, in the three-flavour oscillation case, P{alpha,beta} is different from P{beta,alpha} for a significant portion of the parameter space, even if there is no CP-violating phase in the MNS matrix. Furthermore, P{mu,mu} has a significantly different behaviour from P{tau,tau}, which may affect expectations for the number of events detected at large neutrino telescopes.Comment: 38 pages, 10 figure

    Matter effects and CP violating neutrino oscillations with non-decoupling heavy neutrinos

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    The evolution equation for active and sterile neutrinos propagating in general anisotropic or polarized background environment is found and solved for a special case when heavy neutrinos do not decouple, resulting in non-unitary mixing among light neutrino states. Then new CP violating neutrino oscillation effects appear. In contrast to the standard unitary neutrino oscillations these effects can be visible even for two flavour neutrino transitions and even if one of the elements of the neutrino mixing matrix is equal to zero. They do not necessarily vanish with ÎŽm2→0\delta m^{2} \to 0 and they are different for various pairs of flavour neutrino transitions (Îœe→ΜΌ\nu_e \to \nu_\mu), (ΜΌ→Μτ\nu_\mu \to \nu_\tau), (Μτ→Μe\nu_\tau \to \nu_e). Neutrino oscillations in vacuum and Earth's matter are calculated for some fixed baseline experiments and a comparison between unitary and non-unitary oscillations are presented. It is shown, taking into account the present experimental constraints, that heavy neutrino states can affect CP and T asymmetries. This is especially true in the case of ΜΌ→Μτ\nu_\mu \to \nu_\tau oscillations.Comment: 18 pages, 6 fig

    SN1987A and the Status of Oscillation Solutions to the Solar Neutrino Problem (including an appendix discussing the NC and day/night data from SNO)

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    We study neutrino oscillations and the level-crossing probability PLZ in power-law potential profiles A(r)\propto r^n. We give local and global adiabaticity conditions valid for all mixing angles theta and discuss different representations for PLZ. For the 1/r^3 profile typical of supernova envelopes we compare our analytical to numerical results and to earlier approximations used in the literature. We then perform a combined likelihood analysis of the observed SN1987A neutrino signal and of the latest solar neutrino data, including the recent SNO CC measurement. We find that, unless all relevant supernova parameters (released binding energy, \bar\nu_e and \bar\nu_{\mu,\tau} temperatures) are near their lowest values found in simulations, the status of large mixing type solutions deteriorates considerably compared to fits using only solar data. This is sufficient to rule out the vacuum-type solutions for most reasonable choices of astrophysics parameters. The LOW solution may still be acceptable, but becomes worse than the SMA-MSW solution which may, in some cases, be the best combined solution. On the other hand the LMA-MSW solution can easily survive as the best overall solution, although its size is generally reduced when compared to fits to the solar data only.Comment: 31 pages, 32 eps figures; 5 pages, 5 eps figures addendum in v2, discussing the recent SNO NC data and changes in SN paramete
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