3,776 research outputs found
Evaluation of the Potential of Lactobacillus paracasei Adjuncts for Flavor Compounds Development and Diversification in Short-Aged Cheddar Cheese
peer-reviewedThe non-starter microbiota of Cheddar cheese mostly comprises mesophilic lactobacilli, such as Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus plantarum. These bacteria are recognized for their potential to improve Cheddar cheese flavor when used as adjunct cultures. In this study, three strains of L. paracasei (DPC2071, DPC4206, and DPC4536) were evaluated for their contribution to the enhancement and diversification of flavor in short-aged Cheddar cheese. The strains were selected based on their previously determined genomic diversity, variability in proteolytic enzyme activities and metabolic capability in cheese model systems. The addition of adjunct cultures did not affect the gross composition or levels of lipolysis of the cheeses. The levels of free amino acids (FAA) in cheeses showed a significant increase after 28 days of ripening. However, the concentrations of individual amino acids in the cheeses did not significantly differ except for some amino acids (aspartic acid, threonine, serine, and tryptophan) at Day 14. Volatile profile analysis revealed that the main compounds that differentiated the cheeses were of lipid origin, such as long chain aldehydes, acids, ketones, and lactones. This study demonstrated that the adjunct L. paracasei strains contributed to the development and diversification of compounds related to flavor in short-aged Cheddar cheeses
A variable absorption feature in the X-ray spectrum of a magnetar
Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly
rotating, isolated neutron stars that sporadically undergo episodes of
long-term flux enhancement (outbursts) generally accompanied by the emission of
short bursts of hard X-rays. This behaviour can be understood in the magnetar
model, according to which these sources are mainly powered by their own
magnetic energy. This is supported by the fact that the magnetic fields
inferred from several observed properties of AXPs and SGRs are greater than -
or at the high end of the range of - those of radio pulsars. In the peculiar
case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing
parameters, whereas a strong field has been proposed to reside in the stellar
interior and in multipole components on the surface. Here we show that the
X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which
depend strongly on the star's rotational phase. This line is interpreted as a
proton cyclotron feature and its energy implies a magnetic field ranging from
2E14 gauss to more than 1E15 gauss.Comment: Nature, 500, 312 (including Supplementary Information
Using UAV acquired photography and structure from motion techniques for studying glacier landforms: application to the glacial flutes at IsfallsglaciÀren
Glacier and ice sheet retreat exposes freshly deglaciated terrain which often contains small-scale fragile geomorphological features which could provide insight into subglacial or submarginal processes. Subaerial exposure results in potentially rapid landscape modification or even disappearance of the minor-relief landforms as wind, weather, water and vegetation impact on the newly exposed surface. Ongoing retreat of many ice masses means there is a growing opportunity to obtain high resolution geospatial data from glacier forelands to aid in the understanding of recent subglacial and submarginal processes. Here we used an unmanned aerial vehicle to capture close-range aerial photography of the foreland of IsfallsglaciĂ€ren, a small polythermal glacier situated in Swedish Lapland. An orthophoto and a digital elevation model with ~2âcm horizontal resolution were created from this photography using structure from motion software. These geospatial data was used to create a geomorphological map of the foreland, documenting moraines, fans, channels and flutes. The unprecedented resolution of the data enabled us to derive morphological metrics (length, width and relief) of the smallest flutes, which is not possible with other data products normally used for glacial landform metrics mapping. The map and flute metrics compare well with previous studies, highlighting the potential of this technique for rapidly documenting glacier foreland geomorphology at an unprecedented scale and resolution. The vast majority of flutes were found to have an associated stoss-side boulder, with the remainder having a likely explanation for boulder absence (burial or erosion). Furthermore, the size of this boulder was found to strongly correlate with the width and relief of the lee-side flute. This is consistent with the lee-side cavity infill model of flute formation. Whether this model is applicable to all flutes, or multiple mechanisms are required, awaits further study
The Lightest Pseudo-Goldstone Boson at Future e+e- Colliders
In a class of models of dynamical symmetry breaking not ruled out by the
available data, the lightest neutral pseudo-Nambu-Goldstone boson P0 contains
only down-type techniquarks and charged technileptons. Its mass scale is
naturally determined by the b-quark and therefore it is likely to be light. As
the presence of pseudo-Nambu-Goldstone bosons in models of dynamical symmetry
breaking is a quite general feature, the search of the P0 at colliders is an
interesting opportunity of putting limits on or discovering a dynamical
electroweak symmetry breaking scenario. In this note we discuss the prospects
for discovering and studying the P0 at future e+e- and gamma-gamma colliders.Comment: 15 pages, 8 figures, LaTeX (epsfig), Proceedings of the Second
ECFA/DESY Study on Physics Studies for a Future Linear Collide
Use of ultrasonics in swine improvement
"Today's swine producer must produce pork that is highly acceptable to consumers yet within a cost that permits a profit. Ultrasonics allows objective measurement of back fat and loin-eye area, two traits that recent research has shown to have a close relationship to total red meat in an animal. Progressive swine breeders consider these two highly inheritable carcass traits in their selection programs to increase the red meat portion of animals."--First page.M.A. Alexander, J.W. Massey, J.C. Rea, and R.O. Bates (Department of Animal Science, College of Agriculture)Revised 5/88/10
Studies of factors affecting performance of growing-finishing lambs
This bulletin is a report on Department of Animal Husbandry Research Project 356, 'Lamb fattening'--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 61-65)
Our distorted view of magnetars: application of the Resonant Cyclotron Scattering model
The X-ray spectra of the magnetar candidates are customarily fitted with an
empirical, two component model: an absorbed blackbody and a power-law. However,
the physical interpretation of these two spectral components is rarely
discussed. It has been recently proposed that the presence of a hot plasma in
the magnetosphere of highly magnetized neutron stars might distort, through
efficient resonant cyclotron scattering, the thermal emission from the neutron
star surface, resulting in the production of non-thermal spectra. Here we
discuss the Resonant Cyclotron Scattering (RCS) model, and present its XSPEC
implementation, as well as preliminary results of its application to Anomalous
X-ray Pulsars and Soft Gamma-ray Repeaters.Comment: 5 pages, 5 color figures; Astrophysics & Space Science, in press
("Isolated Neutron Stars"; London, UK
Search for radio pulsations in LS I +61 303
Context. LS I +61 303 is a member of the select group of gamma-ray binaries:
galactic binary systems that contain a massive star and a compact object, show
a changing milliarcsecond morphology and a similar broad spectral energy
distribution (SED) that peaks at MeV-TeV energies and is modulated by the
orbital motion. The nature of the compact object is unclear in LS I +61 303, LS
5039 and HESS J0632+057, whereas PSR B1259-63 harbours a 47.74 ms radio pulsar.
Aims. A scenario in which a young pulsar wind interacts with the stellar wind
has been proposed to explain the very high energy (VHE, E > 100 GeV) gamma-ray
emission detected from LS I +61 303, although no pulses have been reported from
this system at any wavelength. We aim to find evidence of the pulsar nature of
the compact object. Methods. We performed phased array observations with the
Giant Metrewave Radio Telescope (GMRT) at 1280 MHz centred at phase 0.54.
Simultaneous data from the multi-bit phased array (PA) back-end with a sampling
time of tsamp = 128 microsec and from the polarimeter (PMT) back-end with tsamp
= 256 microsec where taken. Results. No pulses have been found in the data set,
with a minimum detectable mean flux density of \sim 0.38 mJy at 8-sigma level
for the pulsed emission from a putative pulsar with period P >2 ms and duty
cycle D = 10% in the direction of LS I +61 303. Conclusions. The detection of
posible radio pulsations will require deep and sensitive observations at
frequencies \sim0.5-5 GHz and orbital phases 0.6-0.7. However, it may be
unfeasible to detect pulses if the putative pulsar is not beamed at the Earth
or if there is a strong absorption within the binary system.Comment: 8 pages. 5 figures. Accepted for publication in Astronomy and
Astrophysic
Movement along a low-angle normal fault: The S reflector west of Spain
[1] The existence of normal faults that moved at low angles (less than 20°) has long been debated. One possible low-angle fault is the S detachment at the west Galicia (Spain) margin and thought to occur at the top of serpentinized mantle. It is unlikely that S was a large submarine slide as it was probably active over several million years without the development of any compressional features such as toe thrusts, it appears to have rooted beneath the conjugate Flemish Cap margin, and it is similar to structures elsewhere that also appear to be rooted detachments. Here we analyze depth images to identify synrift sediment packages above S and use the geometry of these synrift packages to constrain the angle at which S both formed and remained active. We find that S must have remained active at angles below 15°, too low to be explained simply by the low friction coefficient of partially serpentinized peridotites. Instead, we suggest that transient high fluid pressures must have developed within the serpentinites and propose a model in which anastomosing fault strands are alternately active and sealed, enabling moderately high fluid pressures to develop
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