446 research outputs found
More frequencies of KUV 02464+3239
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
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
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
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
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
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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