1,293 research outputs found

    Effects of Caffeine on the Seed Germination of Bambara Groundnut (Vigna subterranean (L.) Verdc)

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    This study was conducted to determine the effects of different caffeine concentrations on seed germination of Bambara groundnut. The seeds were pre-soaked in distilled water for 12 hours and then exposed to the different concentrations of the caffeine doses prepared on weight basis, i.e. 0.005 %, 0.25 %, 0.5 %, and 0.75 % 1.0 %, 1.25 %, 1.5%, 1.75% and 2.0% w/w caffeine in solution, prepared in a phosphate buffer of pH-7 2. Three replications of the treatments were made and sown with each seed of the treated concentrations in a pot using a Complete Randomized Block Design (CRBD). Seed germination was scored for seven days and the germinated seedlings were further observed for 9 weeks. The radicle length, shoot height, and stem girth were measured weekly after germination. From the results, it was evident that increased concentration of caffeine reduced the germination percentage of the seeds. The caffeine concentrations of 1.75-2.0% recorded no germination compared with more than 90% germination at the end of the 7 days recorded in the case of 0.05-0.25% caffeine concentrations. There was a reduction in radicle length as the caffeine concentration increased at 7 weeks after planting. 0.5% caffeine concentration recorded the highest shoot length of 3.32cm among the caffeine concentrations with no significant difference detected in the stem girth studied. From the results obtained therefore, lower caffeine concentrations showed an increase in Bambara groundnut germination, hence could result in general improvement in crop yield.Keywords: Bambara nuts, Caffeine, Crop, Germination, Vigna, Yol

    SPG10 is a rare cause of spastic paraplegia in European families

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    Background: SPG10 is an autosomal dominant form of hereditary spastic paraplegia (HSP), which is caused by mutations in the neural kinesin heavy chain KIF5A gene, the neuronal motor of fast anterograde axonal transport. Only four mutations have been identified to date.Objective: To determine the frequency of SPG10 in European families with HSP and to specify the SPG10 phenotype.Patients and methods: 80 index patients from families with autosomal dominant HSP were investigated for SPG10 mutations by direct sequencing of the KIF5A motor domain. Additionally, the whole gene was sequenced in 20 of these families.Results: Three novel KIF5A mutations were detected in German families, including one missense mutation (c.759G>T, p.K253N), one in frame deletion (c.768_770delCAA, p.N256del) and one splice site mutation (c.217G>A). Onset of gait disturbance varied from infancy to 30 years of age. All patients presented clinically with pure HSP, but a subclinical sensory--motor neuropathy was detected by neurophysiology studies.Conclusions: SPG10 accounts for approximately 3% of European autosomal dominant HSP families. All mutations affect the motor domain of kinesin and thus most likely impair axonal transport. Clinically, SPG10 is characterised by spastic paraplegia with mostly subclinical peripheral neuropathy

    Eimeria spp. and Tyzzeria perniciosa Allen, 1936 (Apicomplexa: Eimeriidae) from a Pacific black duck, Anas superciliosa Gmelin (Aves: Anseriformes), in western Australia

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    Four species of the Eimeriidae, Eimeria anatis Scholtyseck, 1955, Eimeria aythyae Farr, 1965, Eimeria krylovi Svanbaev & Rakhmatullina, 1967 and Tyzzeria perniciosa Allen, 1936, were morphologically identified from oöcysts recovered from a Pacific black duck, Anas superciliosa Gmelin. Additionally, genotypic characterization of E. anatis is provided via sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) and the small subunit ribosomal RNA (18S) genes. The four species are redescribed, providing additional morphological details. The validity of genera and coccidian species parasitizing birds of the order Anseriformes such as Wenyonella Hoare, 1933 and some Tyzzeria spp. are discussed. Molecular phylogenetic analyses for the cox1 and 18S rRNA genes resulted in monophylies of Eimeria spp. from Anseriformes which included the sequences obtained from E. anatis oöcysts

    Higher-order mutual coherence of optical and matter waves

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    We use an operational approach to discuss ways to measure the higher-order cross-correlations between optical and matter-wave fields. We pay particular attention to the fact that atomic fields actually consist of composite particles that can easily be separated into their basic constituents by a detection process such as photoionization. In the case of bosonic fields, that we specifically consider here, this leads to the appearance in the detection signal of exchange contributions due to both the composite bosonic field and its individual fermionic constituents. We also show how time-gated counting schemes allow to isolate specific contributions to the signal, in particular involving different orderings of the Schr\"odinger and Maxwell fields.Comment: 11 pages, 2 figure

    Stability Indicating High-Performance Liquid Chromatography Method for the Estimation of Artemether in Capsule Dosage Forms

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    A new simple, sensitive, precise, and accurate high-performance liquid chromatography (HPLC) method of analysis for artemether both as a bulk drug and in capsule formulations was developed and validated. The method employed mobile phase acetonitrile (ACN) and buffer in the ratio 65:35 of pH 6.5 adjusted with tryethylamine. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.9996 in the concentration range 250-750 μg/ml. The mean value slope and intercept were 9355.5 and −93.5, respectively. The method was validated for precision, accuracy, and recovery studies. Limit of detection (LOD) and Limit of quantitation (LOQ) for artemether were found to be 21.83-750 μg/ml, respectively. The method has been successfully applied in the analysis of marketed capsule formulations. The presented method was found to be reliable to separate all the degradents from all the stress conditions with resolution of more than 1.5 showing that it is a stability indicating method

    A comment on multiple vacua, particle production and the time dependent AdS/CFT correspondence

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    We give an explicit formulation of the time dependent AdS/CFT correspondence when there are multiple vacua present in Lorentzian signature. By computing sample two point functions we show how different amplitudes are related by cosmological particle production. We illustrate our methods in two example spacetimes: (a) a ``bubble of nothing'' in AdS space, and (b) an asymptotically locally AdS spacetime with a bubble of nothing on the boundary. In both cases the alpha vacua of de Sitter space make an interesting appearance.Comment: 9 page

    Test of Sum Rules in Nucleon Transfer Reactions

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    The quantitative consistency of nucleon transfer reactions as a probe of the occupancy of valence orbits in nuclei is tested. Neutron-adding, neutron-removal, and proton-adding transfer reactions were measured on the four stable even Ni isotopes, with particular attention to the cross section determinations. The data were analyzed consistently in terms of the distorted wave Born approximation to yield spectroscopic factors. Valence-orbit occupancies were extracted, utilizing the Macfarlane-French sum rules. The deduced occupancies are consistent with the changing number of valence neutrons, as are the vacancies for protons, both at the level of <5%. While there has been some debate regarding the true “observability” of spectroscopic factors, the present results indicate that empirically they yield self-consistent results

    Motion of Inertial Observers Through Negative Energy

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    Recent research has indicated that negative energy fluxes due to quantum coherence effects obey uncertainty principle-type inequalities of the form |\Delta E|\,{\Delta \tau} \lprox 1\,. Here ΔE|\Delta E| is the magnitude of the negative energy which is transmitted on a timescale Δτ\Delta \tau. Our main focus in this paper is on negative energy fluxes which are produced by the motion of observers through static negative energy regions. We find that although a quantum inequality appears to be satisfied for radially moving geodesic observers in two and four-dimensional black hole spacetimes, an observer orbiting close to a black hole will see a constant negative energy flux. In addition, we show that inertial observers moving slowly through the Casimir vacuum can achieve arbitrarily large violations of the inequality. It seems likely that, in general, these types of negative energy fluxes are not constrained by inequalities on the magnitude and duration of the flux. We construct a model of a non-gravitational stress-energy detector, which is rapidly switched on and off, and discuss the strengths and weaknesses of such a detector.Comment: 18pp + 1 figure(not included, available on request), in LATEX, TUPT-93-

    Valence nucleon populations in the Ni isotopes

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    Measurements of neutron-adding, neutron-removing, and proton-adding reactions were carried out for the four stable even Ni isotopes. Particular attention was paid to obtaining precise values of the cross sections at the peaks of the angular distributions. Tests with sum rules for the neutron data indicate that the results are self-consistent at the level of a few tenths of a nucleon. Data on proton-adding reactions were also obtained and analyzed with a slightly different method—while these data are also consistent, the ambiguities are larger. The occupancies of the neutron orbits derived from the data, the proton vacancies, and the energy centroids of the neutron, neutron-hole, and proton single-particle excitations are obtained. The data also provide some estimate about the closure of the 0f7/2 shell. The results are compared to shell-model calculations and may serve as a reference point for future exploration

    Averaged Energy Conditions and Evaporating Black Holes

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    In this paper the averaged weak (AWEC) and averaged null (ANEC) energy conditions, together with uncertainty principle-type restrictions on negative energy (``quantum inequalities''), are examined in the context of evaporating black hole backgrounds in both two and four dimensions. In particular, integrals over only half-geodesics are studied. We determine the regions of the spacetime in which the averaged energy conditions are violated. In all cases where these conditions fail, there appear to be quantum inequalities which bound the magnitude and extent of the negative energy, and hence the degree of the violation. The possible relevance of these results for the validity of singularity theorems in evaporating black hole spacetimes is discussed.Comment: Sections 2.1 and 2.2 have been revised and some erroneous statements corrected. The main conclusions and the figures are unchanged. 27 pp, plain Latex, 3 figures available upon reques
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