4,264 research outputs found
Dark matter voids in the SDSS galaxy survey
What do we know about voids in the dark matter distribution given the Sloan
Digital Sky Survey (SDSS) and assuming the model? Recent
application of the Bayesian inference algorithm BORG to the SDSS Data Release 7
main galaxy sample has generated detailed Eulerian and Lagrangian
representations of the large-scale structure as well as the possibility to
accurately quantify corresponding uncertainties. Building upon these results,
we present constrained catalogs of voids in the Sloan volume, aiming at a
physical representation of dark matter underdensities and at the alleviation of
the problems due to sparsity and biasing on galaxy void catalogs. To do so, we
generate data-constrained reconstructions of the presently observed large-scale
structure using a fully non-linear gravitational model. We then find and
analyze void candidates using the VIDE toolkit. Our methodology therefore
predicts the properties of voids based on fusing prior information from
simulations and data constraints. For usual void statistics (number function,
ellipticity distribution and radial density profile), all the results obtained
are in agreement with dark matter simulations. Our dark matter void candidates
probe a deeper void hierarchy than voids directly based on the observed
galaxies alone. The use of our catalogs therefore opens the way to
high-precision void cosmology at the level of the dark matter field. We will
make the void catalogs used in this work available at
http://www.cosmicvoids.net.Comment: 15 pages, 6 figures, matches JCAP published version, void catalogs
publicly available at http://www.cosmicvoids.ne
SECONDARY EFFECT OF 8-AZAGUANINE ON THE INDUCED OR CONSTITUTIVE SYNTHESIS OF PENICILLINASE IN BACILLUS CEREUS. EUR 509.e
1. 1. During the restoration of protein synthesis caused by guanosine after inhibition by azaguanine, the differential rate of synthesis of penicillinase (penicillin amidohydrolase, EC 3.5.2.6) is much reduced. 2. 2. This effect is observed irrespective of the state of induction, or repression, of the penicillinase-making system during the action of azaguanine. © 1963.SCOPUS: ar.jSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Design of a low-noise aeroacoustic wind tunnel facility at Brunel University
This paper represents the design principle of a quiet, low turbulence and moderately high speed aeroacoustic wind tunnel which was recently commissioned at Brunel University. A new hemi-anechoic chamber was purposely built to facilitate aeroacoustic measurements. The wind tunnel can achieve a maximum speed of about 80 ms-1. The turbulence intensity of the free jet in the potential core is between 0.1–0.2%. The noise characteristic of the aeroacoustic wind tunnel was validated by three case studies. All of which can demonstrate a very low background noise produced by the bare jet in comparison to the noise radiated from the cylinder rod/flat plate/airfoil in the air stream.The constructions of the aeroacoustic wind tunnel and the hemi-anechoic chamber are financially supported by the School of Engineering and Design at Brunel University
The 8 Learning Events Model: a Pedagogic Conceptual Tool Supporting Diversification of Learning Methods
This paper presents the 8 Learning Events Model (8LEM), a pedagogical reference framework which was used, in more than 100 online course, as a starting point for instructional planning. Besides supporting teachers in early stages of the learning design continuum, the paper shows how this learning/teaching model, as a professional development tool, prompts them to diversify the learning methods experienced by students in their courses. A two-pronged rationale about the importance of this diversification with respect to "mathetic" competence development and epistemology is also proposed to discussion. Keywords: mathetical competences, learning methods, teacher's professional development
The 8 Learning Events Model: a Pedagogic Conceptual Tool Supporting Diversification of Learning Methods
This paper presents the 8 Learning Events Model (8LEM), a pedagogical reference framework which was used, in more than 100 online course, as a starting point for instructional planning. Besides supporting teachers in early stages of the learning design continuum, the paper shows how this learning/teaching model, as a professional development tool, prompts them to diversify the learning methods experienced by students in their courses. A two-pronged rationale about the importance of this diversification with respect to "mathetic" competence development and epistemology is also proposed to discussion. Keywords: mathetical competences, learning methods, teacher's professional development
Strong obstruction of the Berends-Burgers-van Dam spin-3 vertex
In the eighties, Berends, Burgers and van Dam (BBvD) found a nonabelian cubic
vertex for self-interacting massless fields of spin three in flat spacetime.
However, they also found that this deformation is inconsistent at higher order
for any multiplet of spin-three fields. For arbitrary symmetric gauge fields,
we severely constrain the possible nonabelian deformations of the gauge algebra
and, using these results, prove that the BBvD obstruction cannot be cured by
any means, even by introducing fields of spin higher (or lower) than three.Comment: 19 pages, no figur
Development of Lumped Element Kinetic Inductance Detectors for NIKA
Lumped-element kinetic inductance detectors(LEKIDs) have recently shown
considerable promise as direct absorption mm-wavelength detectors for
astronomical applications. One major research thrust within the N\'eel Iram
Kids Array (NIKA) collaboration has been to investigate the suitability of
these detectors for deployment at the 30-meter IRAM telescope located on Pico
Veleta in Spain. Compared to microwave kinetic inductance detectors (MKID),
using quarter wavelength resonators, the resonant circuit of a LEKID consists
of a discrete inductance and capacitance coupled to a feedline. A high and
constant current density distribution in the inductive part of these resonators
makes them very sensitive. Due to only one metal layer on a silicon substrate,
the fabrication is relatively easy. In order to optimize the LEKIDs for this
application, we have recently probed a wide variety of individual resonator and
array parameters through simulation and physical testing. This included
determining the optimal feed-line coupling, pixel geometry, resonator
distribution within an array (in order to minimize pixel cross-talk), and
resonator frequency spacing. Based on these results, a 144-pixel Aluminum array
was fabricated and tested in a dilution fridge with optical access, yielding an
average optical NEP of ~2E-16 W/Hz^1/2 (best pixels showed NEP = 6E-17 W/Hz^1/2
under 4-8 pW loading per pixel). In October 2010 the second prototype of LEKIDs
has been tested at the IRAM 30 m telescope. A new LEKID geometry for 2
polarizations will be presented. Also first optical measurements of a titanium
nitride array will be discussed.Comment: 5 pages, 12 figures; ISSTT 2011 Worksho
High-quality fully relaxed In0.65Ga0.35As layers grown on InP using the paramorphic approach
International audienceThin and thick fully relaxed In 0.65 Ga 0.35 As layers have been grown on InP substrates 0.81% misfit, with high structural and high optoelectronic quality at an operating wavelength of 2.0 m. Full relaxation is achieved, using the paramorphic approach, by growing the In 0.65 Ga 0.35 As layers lattice matched to an InAs 0.25 P 0.75 seed membrane of predetermined lattice parameter. The InAs 0.25 P 0.75 layer was originally grown pseudomorphically strained on the InP substrate before being separated and elastically relaxed using surface micromachining
Contribución al estudio de los dípteros malacófagos (Sciomyzidae) de la península ibérica, Baleares y Canarias
Abstract not availabl
Yeast cell wall extracts from Saccharomyces cerevisiae varying in structure and composition differentially shape the innate immunity and mucosal tissue responses of the intestine of zebrafish (Danio rerio)
With the rising awareness of antimicrobial resistance, the development and use of functional feed additives (FFAs) as an alternative prophylactic approach to improve animal health and performance is increasing. Although the FFAs from yeasts are widely used in animal and human pharma applications already, the success of future candidates resides in linking their structural functional properties to their efficacy in vivo. Herein, this study aimed to characterise the biochemical and molecular properties of four proprietary yeast cell wall extracts from S. cerevisiae in relation to their potential effect on the intestinal immune responses when given orally. Dietary supplementation of the YCW fractions identified that the α-mannan content was a potent driver of mucus cell and intraepithelial lymphocyte hyperplasia within the intestinal mucosal tissue. Furthermore, the differences in α-mannan and β-1,3-glucans chain lengths of each YCW fraction affected their capacity to be recognised by different PRRs. As a result, this affected the downstream signalling and shaping of the innate cytokine milieu to elicit the preferential mobilisation of effector T-helper cell subsets namely Th17, Th1, Tr1 and FoxP3+-Tregs. Together these findings demonstrate the importance of characterising the molecular and biochemical properties of YCW fractions when assessing and concluding their immune potential. Additionally, this study offers novel perspectives in the development specific YCW fractions derived from S. cerievisae for use in precision animal feeds
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