83 research outputs found

    Selected cultivars of cornelian cherry (Cornus mas L.) as a new food source for human nutrition

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    The aim of this work was to determine antioxidant activity in 12 cultivars of cornelian cherry (Cornusmas L.). Two assays based on ion reduction of ABTS (2,2´-azinobis(3-ethylbenzothiazoline-6-sulphonate) and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals were used for antioxidant activity. Totalphenolic content of the fruit was analysed by Folin-Ciocelteau colorimetric method and ascorbic acidcontent was analysed using column chromatography - electrochemical detector (Coulochem III). Thehighest amounts of total phenolic content were found in cultivars ´Vydubeckij´ and ´Titus´ as 7.96 and8.11 g gallic acid kg-1 of fresh mass (FM). High correlation between polyphenols and antioxidant activityin fruits of the cultivars was observed (r2 = 0.970 for DPPH test and r2 = 0.978 for ABTS test). Thehighest total content of ascorbic acid was determined in cultivar ´Olomoucky´, with the value of 3.11 gkg-1 FM. This study attempts to contribute to the knowledge of human nutritional properties of thesecornelian cherry cultivars and may be useful for the evaluation of dietary information and furtherpropagation of cultivation and utilization of this fruit in the world

    Influence of Special Needs Education Policy on Access to Secondary School Education By Learners With Hearing Impairments In Nandi County, Kenya

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    This study sought to examine influence of Special Needs Education Policy on access to secondary school education by learners with hearing impairments in Nandi County, Kenya. The study was informed by the Multiple Intelligences theory and the Dewey theory of Progressivism. The findings showed that majority of the respondents were aware of the Special Needs Education Policy Framework of 2009 and believed that the policy was being implemented. Majority of the respondents felt that the implementation of the policy had positively affected learners’ enrolment in schools but recognized that there were still several challenges that were acting as barriers to school access by learners with hearing impairments in Nandi County. Further, the respondents observed that the implementation of the Special Needs Education Policy had led to a slight improvement on transition of learners with hearing impairments from primary to secondary schools in Nandi County. The influence of the Special Needs Education Policy on retention of learners with hearing impairments was deemed to be marginally small in schools in Nandi County. The results also showed that there were cases of learners dropping out of school because of a number of reasons including financial problems, lack of motivation to be in school and cultural factors, among others. In order to improve access to school education by learners with hearing impairments, respondents gave their opinions on how the challenges could be handled including the need to train more teachers to teach learners with hearing impairments, provision of adequate learning materials and the need to fund the special units/schools for the hearing impaired in the county, among others. The study recommends that the Government should set clear guidelines on how the Special Needs Education Policy can be implemented and coordinated. The study also recommends increase of necessary support for the secondary and primary school/units for the hearing impaired in the county so as to improve access to school education by children with hearing impairments. Keywords: special needs policy, hearing impairment, access to educatio

    QSO 2237+0305 VR light curves from Gravitational Lenses International Time Project optical monitoring

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    We present VR observations of QSO 2237+0305 conducted by the GLITP collaboration from 1999 October 1 to 2000 February 3. The observations were made with the 2.56 m Nordic Optical Telescope at Roque de los Muchachos Observatory, La Palma (Spain). The PSF fitting method and an adapted version of the ISIS subtraction method have been used to derive the VR light curves of the four components (A-D) of the quasar. The mean errors range in the intervals 0.01-0.04 mag (PSF fitting) and 0.01-0.02 mag (ISIS subtraction), with the faintest component (D) having the largest uncertainties. We address the relatively good agreement between the A-D light curves derived using different filters, photometric techniques, and telescopes. The new VR light curves of component A extend the time coverage of a high magnification microlensing peak, which was discovered by the OGLE team.Comment: 15 pages, 3 figures, ApJ accepted (Feb 19

    Adiabatic invariants and Mixmaster catastrophes

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    We present a rigorous analysis of the role and uses of the adiabatic invariant in the Mixmaster dynamical system. We propose a new invariant for the global dynamics which in some respects has an improved behaviour over the commonly used one. We illustrate its behaviour in a number of numerical results. We also present a new formulation of the dynamics via Catastrophe Theory. We find that the change from one era to the next corresponds to a fold catastrophe, during the Kasner shifts the potential is an Implicit Function Form whereas, as the anisotropy dissipates, the Mixmaster potential must become a Morse 0--saddle. We compare and contrast our results to many known works on the Mixmaster problem and indicate how extensions could be achieved. Further exploitation of this formulation may lead to a clearer understanding of the global Mixmaster dynamics.Comment: 24 pages, LaTeX, 5 figures (which can be obtained by sending a message to the first author), submitted to Phys.Rev.

    Quince (Cydonia oblonga) in vitro plant root formation through an automated temporary inmersion system, and its acclimation

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    Artículo científicoQuince (Cydonia oblonga) is a non-traditional fruit tree found in Costa Rica that has therapeutic and nutritional properties; however its slow growth and root formation prevents the production of a homogeneous population when using conventional farming techniques. Hence, the aim of this research project was to generate uniform plant material in a reduced time span using a temporary immersion bioreactor system (RITAS Ÿ). A semisolid rooting MS culture medium supplemented with 0.1 mg L-1 NAA; 0.3 mg L-1 IBA and 3% sucrose (pH 6.5), developed in the Centro de Investigación en Biotecnología (CIB), Instituto Tecnológico de Costa Rica (ITCR), in Cartago, was used as a reference medium. Four different variations in the sucrose concentration (1%, 2%, 3%, and 4%) were performed in liquid medium. Each trial was evaluated with in vitro plants which had been previously exposed to the culture medium of the corresponding treatments, in a stationary mode and for a 15 day long period, and with in vitro plants without any previous treatment (a total of eight treatments). The comparison of the root formation percentages evidenced the clear effect of sucrose concentration used, with the best results obtained when using the 2% sucrose trial with no pre-treatment (73.3%). The in vitro plants were acclimated in cylinders made out of peat, have previously been disinfected with fungicide, and placed in a humidity chamber at a 20.5°C average temperature and a 75,5% relative humidity for the establishment of weekly fertilizing cycles. The acclimation process generated an 80% survival rate, since several seedlings experienced stem strangulation caused by a fungal attack. The conidiophores identified through optical and scanning electron microscopy evidenced the presence of Cladosporium spp., which was controlled with carbendazim and iprodione fungicides

    Helium in the eroding atmosphere of an exoplanet.

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    Helium is the second-most abundant element in the Universe after hydrogen and is one of the main constituents of gas-giant planets in our Solar System. Early theoretical models predicted helium to be among the most readily detectable species in the atmospheres of exoplanets, especially in extended and escaping atmospheres 1 . Searches for helium, however, have hitherto been unsuccessful 2 . Here we report observations of helium on an exoplanet, at a confidence level of 4.5 standard deviations. We measured the near-infrared transmission spectrum of the warm gas giant 3 WASP-107b and identified the narrow absorption feature of excited metastable helium at 10,833 angstroms. The amplitude of the feature, in transit depth, is 0.049 ± 0.011 per cent in a bandpass of 98 angstroms, which is more than five times greater than what could be caused by nominal stellar chromospheric activity. This large absorption signal suggests that WASP-107b has an extended atmosphere that is eroding at a total rate of 1010 to 3 × 1011 grams per second (0.1-4 per cent of its total mass per billion years), and may have a comet-like tail of gas shaped by radiation pressure
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