446 research outputs found

    More frequencies of KUV 02464+3239

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    Preliminary results on KUV 02464+3239, a pulsating DA white dwarf are presented. Located near the red edge of the DAV instability strip, KUV 02464+3239 shows large amplitude and long period pulsation modes. Up to now only one mode was known from a 50-minute-long light curve. Our more extended observations allowed the identification of three additional frequencies. The presence of previously known harmonics were confirmed and weak subharmonics are also noticeable at some parts of the light curve. This suggests the dominance of nonlinear pulsation effects from time to time.Comment: 3 pages, 3 eps figures; has been accepted for publication in Astronomische Nachrichten (Vol. 8, 2007), proceedings of the British-Hungarian-French N+N+N Workshop for Young Researcher

    Chemical Raman Enhancement of Organic Adsorbates on Metal Surfaces

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    Using a combination of first-principles theory and experiments, we provide a quantitative explanation for chemical contributions to surface-enhanced Raman spectroscopy for a well-studied organic molecule, benzene thiol, chemisorbed on planar Au(111) surfaces. With density functional theory calculations of the static Raman tensor, we demonstrate and quantify a strong mode-dependent modification of benzene thiol Raman spectra by Au substrates. Raman active modes with the largest enhancements result from stronger contributions from Au to their electron-vibron coupling, as quantified through a deformation potential, a well-defined property of each vibrational mode. A straightforward and general analysis is introduced that allows extraction of chemical enhancement from experiments for specific vibrational modes; measured values are in excellent agreement with our calculations.Comment: 5 pages, 4 figures and Supplementary material included as ancillary fil

    Blackleg of rapeseed

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    Unless blackleg can be controlled there is little future for rapeseed as a major commercial crop in W.A. Until 1972, oilseed rape showed great promise as an alternative cash crop for Western Australian farmers, especially in the Great Southern and south coastal areas. However, like most other cruciferous crops, rape is prone to attack from diseases and insect pests. Most of these can be controlled, but the fungus disease blackleg (Leptosphaeria maculans) emerged as a major threat to the industry. Clearly, unless the disease can be controlled, there is little future for rapeseed as a major commercial crop in Western Australia

    Nmr relaxation studies on the hydrate layer of intrinsically unstructured proteins

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    Intrinsically unstructured/ disordered proteins (IUPs) exist in a disordered and largely solvent- exposed, still functional, structural state under physiological conditions. As their function is often directly linked with structural disorder, understanding their structure-function relationship in detail is a great challenge to structural biology. In particular, their hydration and residual structure, both closely linked with their mechanism of action, require close attention. Here we demonstrate that the hydration of IUPs can be adequately approached by a technique so far unexplored with respect to IUPs, solid-state NMR relaxation measurements. This technique provides quantitative information on various features of hydrate water bound to these proteins. By freezing nonhydrate ( bulk) water out, we have been able to measure free induction decays pertaining to protons of bound water from which the amount of hydrate water, its activation energy, and correlation times could be calculated. Thus, for three IUPs, the first inhibitory domain of calpastatin, microtubule-associated protein 2c, and plant dehydrin early responsive to dehydration 10, we demonstrate that they bind a significantly larger amount of water than globular proteins, whereas their suboptimal hydration and relaxation parameters are correlated with their differing modes of function. The theoretical treatment and experimental approach presented in this article may have general utility in characterizing proteins that belong to this novel structural class

    Three-Dimensional Optical Transformer - Highly Efficient Nanofocusing Device

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    Using electron-beam-induced deposition and focused-ion-beam milling, we have fabricated and demonstrated a nanofocusing optical transformer with a 3-dimensionally tapered tip. At the tip, the light is confined to 13-by-80-nm area with intensity enhancement exceeding 1500

    Systematic review of fatty acid composition of human milk from mothers of preterm compared to full-term infants

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    Background: Fatty acid composition of human milk serves as guidance for the composition of infant formulae. The aim of the study was to systematically review data on the fatty acid composition of human milk of mothers of preterm compared to full-term infants. Methods: An electronic literature search was performed in English (Medline and Medscape) and German (SpringerLink) databases and via the Google utility. Fatty acid compositional data for preterm and fullterm human milk were converted to differences between means and 95% confidence intervals. Results: We identified five relevant studies publishing direct comparison of fatty acid composition of preterm versus full-term human milk. There were no significant differences between the values of the principal saturated and monounsaturated fatty acids. In three independent studies covering three different time points of lactation, however, docosahexaenoic acid (DHA) values were significantly higher in milk of mothers of preterm as compared to those of full-term infants, with an extent of difference considered nutritionally relevant. Conclusion: Higher DHA values in preterm than in full-term human milk underlines the importance of using own mother's milk for feeding preterm babies and raises the question whether DHA contents in preterm formulae should be higher than in formulae for full-term infants. Copyright (c) 2008 S. Karger AG, Basel
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