642 research outputs found
Extraction of ellagitannins from oak wood of model casks
Eight experimental model casks were constructed using wood from four oak trees and filled with a 12 % ethanol solution for 200 days. The concentration of ellagitannins was subsequently measured in the solutions and in the inner and outer faces of the cask wood. Only a low proportion of the total ellagitannins was extracted from the wood, and this proportion varied significantly between both different casks and between the eight ellagitannins measured. The two most abundant ellagitannins, castalagin and vescalagin, were the least easily extracted. The concentration of ellagitannins was much lower in the solutions than expected from calculations based on the difference between the inner and outer faces of the wood. This degradation of ellagitannins occurs subsequent to their extraction into solution
Quality Assessment of Oenological Tannins Utilising Global Selectivity Chemical Sensors Array (âElectronic Tongueâ)
Oenological tannin is a common name for food additives containing tannins utilised in winemaking practices. The maintaste feature of oenological tannin is the taste sensation of astringency and bitterness. In the present paper, samples ofvarious oenological tannins (oak, chestnut, gall, tara, querbacho, grape seed and grape skin tannins) were analysed bymeans of a tasting panel, measuring the flavour attributes bitterness, astringency, body, duration of flavour and similaritywith wine tannins, and using the array of global selectivity chemical sensors (electronic tongue) âα-ASTREEâ Liquid andTaste Analyzer (Alpha M.O.S., Toulouse, France). Principal component analysis of the electronic tongue outputs appliedfor different tannin solutions provides good discrimination according to their chemical nature. Consequently, three mainclasses of oenological tannins, namely gallotannins, ellagitannins and condensed tannins, could be identified and separated.The global output of the electronic tongue is quite responsive to changes in the bitterness and astringency of model quinineand alum solutions and, once calibrated (correlation coefficients of 0.976 (p<0.001) and 0.996 (p<0.001) respectively) couldquantify their concentrations with good precision. The electronic tongue output was found to be correlated with the flavourattributes of oenological tannins. The best correlation was observed for bitterness. This fact could be explained by moreconstant calibration and lesser influence of any interfering factors on this attribute
The Formation of Large Galactic Disks: Revival or Survival?
Using the deepest and the most complete set of observations of distant
galaxies, we investigate how extended disks could have formed. Observations
include spatially-resolved kinematics, detailed morphologies and photometry
from UV to mid-IR. Six billion years ago, half of the present-day spiral
progenitors had anomalous kinematics and morphologies, as well as relatively
high gas fractions. We argue that gas-rich major mergers, i.e., fusions between
gas-rich disk galaxies of similar mass, can be the likeliest driver for such
strong peculiarities. This suggests a new channel of disk formation, e.g. many
disks could be reformed after gas-rich mergers. This is found to be in perfect
agreement with predictions from the state-of-the-art LCDM semi-empirical
models: due to our sensitivity in detecting mergers at all phases, from pairs
to relaxed post-mergers, we find a more accurate merger rate. The scenario can
be finally confronted to properties of nearby galaxies, including M31 and
galaxies showing ultra-faint, gigantic structures in their haloes.Comment: Proceedings of the annual meeting of the French Astronomical Society,
2011, 6 pages, 1 Figur
Galaxy disks do not need to survive in the L-CDM paradigm: the galaxy merger rate out to z~1.5 from morpho-kinematic data
About two-thirds of present-day, large galaxies are spirals such as the Milky
Way or Andromeda, but the way their thin rotating disks formed remains
uncertain. Observations have revealed that half of their progenitors, six
billion years ago, had peculiar morphologies and/or kinematics, which exclude
them from the Hubble sequence. Major mergers, i.e., fusions between galaxies of
similar mass, are found to be the likeliest driver for such strong
peculiarities. However, thin disks are fragile and easily destroyed by such
violent collisions, which creates a critical tension between the observed
fraction of thin disks and their survival within the L-CDM paradigm. Here we
show that the observed high occurrence of mergers amongst their progenitors is
only apparent and is resolved when using morpho-kinematic observations which
are sensitive to all the phases of the merging process. This provides an
original way of narrowing down observational estimates of the galaxy merger
rate and leads to a perfect match with predictions by state-of-the-art L-CDM
semi-empirical models with no particular fine-tuning needed. These results
imply that half of local thin disks do not survive but are actually rebuilt
after a gas-rich major merger occurring in the past nine billion years, i.e.,
two-thirds of the lifetime of the Universe. This emphasizes the need to study
how thin disks can form in halos with a more active merger history than
previously considered, and to investigate what is the origin of the gas
reservoir from which local disks would reform.Comment: 19 pages, 7 figures, 2 tables. Accepted in ApJ. V2 to match proof
corrections and added reference
Effects of Isometric Handgrip Training in Patients With Peripheral Artery Disease: A Randomized Controlled Trial
BackgroundMetaâanalyses have shown that isometric handgrip training (IHT) can reduce brachial systolic and diastolic blood pressure (BP) by >6/4 mm Hg, respectively. However, whether IHT promotes these effects among patients with peripheral artery disease, who exhibit severe impairment in cardiovascular function, is currently unknown. This study aimed to evaluate the effects of IHT on the cardiovascular function of patients with peripheral artery disease.
Methods and ResultsA randomized controlled trial with peripheral artery disease patients assigned to either the IHT or control group was conducted. The IHT group performed 3 sessions per week, for 8 weeks, of unilateral handgrip exercises, consisting of 4 sets of isometric contractions for 2 minutes at 30% of maximum voluntary contraction and a 4âminute interval between sets. The control group received a compression ball in order to minimize the placebo effects, representing sham training. The primary outcome was brachial BP. The secondary outcomes were central BP, arterial stiffness parameters, cardiac autonomic modulation, and vascular function. The IHT program reduced diastolic BP (75 [10] mm Hg preintervention versus 72 [11] mm Hg postintervention), with no change in the control group (74 [11] mm Hg preintervention versus 74 [11] mm Hg postintervention), with this betweenâgroup difference being significant (P=0.04). Flowâmediated dilation improved in the IHT group (6.0% [5.7] preintervention versus 9.7% [5.5] postintervention), with no change in the control group (7.6% [5.5] preintervention versus 7.4% [5.1] postintervention), with this betweenâgroup difference being significant (P=0.04). There was no change in other measured variables over the intervention period.
ConclusionsIHT reduced brachial diastolic BP and improved local vascular function in patients with peripheral artery disease
The Milky Way and other spiral galaxies
Cosmologists have often considered the Milky Way as a typical spiral galaxy,
and its properties have considerably influenced the current scheme of galaxy
formation. Here we compare the general properties of the Milky Way disk and
halo with those of galaxies selected from the SDSS. Assuming the recent
measurements of its circular velocity results in the Milky Way being offset by
~2 sigma from the fundamental scaling relations. On the basis of their location
in the (M_K, R_d, V_flat) volume, the fraction of SDSS spirals like the
MilkyWay is only 1.2% in sharp contrast with M31, which appears to be quite
typical. Comparison of the Milky Way with M31 and with other spirals is also
discussed to investigate whether or not there is a fundamental discrepancy
between their mass assembly histories. Possibly the Milky Way is one of the
very few local galaxies that could be a direct descendant of very distant,
z=2-3 galaxies, thanks to its quiescent history since thick disk formation.Comment: 4 pages, 1 Figure, to appear in the Proceedings of the Conference
"Assembling the Puzzle of the Milky Way", held at Le Grand Bornand, April
201
Looking At the Distant Universe with the MeerKAT Array (LADUMA)
The MeerKAT (64 x 13.5m dish radio interferometer) is South Africa's
precursor instrument for the Square Kilometre Array (SKA), exploring dish
design, instrumentation, and the characteristics of a Karoo desert site and is
projected to be on sky in 2016. One of two top-priority, Key Projects is a
single deep field, integrating for 5000 hours total with the aim to detect
neutral atomic hydrogen through its 21 cm line emission out to redshift unity
and beyond.
This first truly deep HI survey will help constrain fueling models for galaxy
assembly and evolution. It will measure the evolution of the cosmic neutral gas
density and its distribution over galaxies over cosmic time, explore evolution
of the gas in galaxies, measure the Tully-Fisher relation, measure OH maser
counts, and address many more topics.
Here we present the observing strategy and envisaged science case for this
unique deep field, which encompasses the Chandra Deep Field-South (and the
footprints of GOODS, GEMS and several other surveys) to produce a singular
legacy multi-wavelength data-set.Comment: 3 pages, 2 figures, to appear in the proceedings of IAU Symposium
284, "The Spectral Energy Distribution of Galaxies" (SED2011), 5-9 September
2011, Preston, UK, editors R.J. Tuffs & C.C.Popesc
A temperature-controlled device for volumetric measurements of Helium adsorption in porous media
We describe a set-up for studying adsorption of helium in silica aerogels,
where the adsorbed amount is easily and precisely controlled by varying the
temperature of a gas reservoir between 80 K and 180 K. We present validation
experiments and a first application to aerogels. This device is well adapted to
study hysteresis, relaxation, and metastable states in the adsorption and
desorption of fluids in porous media
Oxford SWIFT IFS and multi-wavelength observations of the Eagle galaxy at z=0.77
The `Eagle' galaxy at a redshift of 0.77 is studied with the Oxford Short
Wavelength Integral Field Spectrograph (SWIFT) and multi-wavelength data from
the All-wavelength Extended Groth strip International Survey (AEGIS). It was
chosen from AEGIS because of the bright and extended emission in its slit
spectrum. Three dimensional kinematic maps of the Eagle reveal a gradient in
velocity dispersion which spans 35-75 +/- 10 km/s and a rotation velocity of 25
+/- 5 km/s uncorrected for inclination. Hubble Space Telescope images suggest
it is close to face-on. In comparison with galaxies from AEGIS at similar
redshifts, the Eagle is extremely bright and blue in the rest-frame optical,
highly star-forming, dominated by unobscured star-formation, and has a low
metallicity for its size. This is consistent with its selection. The Eagle is
likely undergoing a major merger and is caught in the early stage of a
star-burst when it has not yet experienced metal enrichment or formed the mass
of dust typically found in star-forming galaxies.Comment: accepted for publication in MNRA
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