580 research outputs found
Research influence on public policy : a case study
French version available in IDRC Digital Library: Négocier un nouveau contexte du commerce international : la recherche à la rescousse de l'Amérique latin
Influence de la recherche sur les politiques : une étude de cas
Version anglaise disponible dans la Bibliothèque numérique du CRDI: Negotiating the new world of international trade : research helps Latin America to cope with an expanding trade dialogu
Charge asymmetry in W + jets production at the LHC
The charge asymmetry in W + jets production at the LHC can serve to calibrate
the presence of New Physics contributions. We study the ratio {\sigma}(W^+ + n
jets)/{\sigma}(W^- + n jets) in the Standard Model for n <= 4, paying
particular attention to the uncertainty in the prediction from higher-order
perturbative corrections and uncertainties in parton distribution functions. We
show that these uncertainties are generally of order a few percent, making the
experimental measurement of the charge asymmetry ratio a particularly useful
diagnostic tool for New Physics contributions.Comment: 13 pages, 7 figures. Reference added. Slightly modified tex
Customizable, engineered substrates for rapid screening of cellular cues
Biophysical cues robustly direct cell responses and are thus important tools for in vitro and translational biomedical applications. High throughput platforms exploring substrates with varying physical properties are therefore valuable. However, currently existing platforms are limited in throughput, the biomaterials used, the capability to segregate between different cues and the assessment of dynamic responses. Here we present a multiwell array (3x8) made of a substrate engineered to present topography or rigidity cues welded to a bottomless plate with a 96-well format. Both the patterns on the engineered substrate and the well plate format can be easily customized, permitting systematic and efficient screening of biophysical cues. To demonstrate the broad range of possible biophysical cues examinable, we designed and tested three multiwell arrays to influence cardiomyocyte, chondrocyte and osteoblast function. Using the multiwell array, we were able to measure different cell functionalities using analytical modalities such as live microscopy, qPCR and immunofluorescence. We observed that grooves (5 µm in size) induced less variation in contractile function of cardiomyocytes. Compared to unpatterned plastic, nanopillars with 127 nm height, 100 nm diameter and 300 nm pitch enhanced matrix deposition, chondrogenic gene expression and chondrogenic maintenance. High aspect ratio pillars with an elastic shear modulus of 16 kPa mimicking the matrix found in early stages of bone development improved osteogenic gene expression compared to stiff plastic. We envisage that our bespoke multiwell array will accelerate the discovery of relevant biophysical cues through improved throughput and variety
Multiple Singular Emission in Gauge Theories
I derive a class of functions unifying all singular limits for the emission
of a given number of soft or collinear gluons in tree-level gauge-theory
amplitudes. Each function is a generalization of the single-emission antenna
function of ref. [1]. The helicity-summed squares of these functions are thus
also generalizations to multiple singular emission of the Catani--Seymour
dipole factorization function.Comment: Corrections for final journal version (sign in eqn. (6.11), equation
references, typos in indices) & removal of comment about FD
Sortilin regulates sorting and secretion of Sonic hedgehog
Sonic Hedgehog (Shh) is a secreted morphogen that is an essential regulator of patterning and growth. The Shh full-length protein undergoes autocleavage in the ER to generate the biologically active amino-terminal ShhN fragment, which is destined for secretion. Few receptors have been identified that control the trafficking of this morphogen through the secretory pathway. We identified Sortilin (Sort1), a member of the VPS10P domain receptor family, as a novel Shh trafficking receptor. We demonstrate that Sort/Shh interact using co-IP and proximity ligation in transfected cells and that they co-localize to the Golgi. Sort1 overexpression causes re-distribution of ShhN, and to a lesser extent ShhFL, to the Golgi and reduces Shh secretion. We show loss of Sort1 can partially rescue Hedgehog-associated patterning defects in a mouse model of deficient Shh processing and that Sort1 levels negatively regulate anterograde Shh transport in axons in vitro and Hh-dependent axon-glial interactions in vivo Taken together, we conclude that Shh and Sort1 can interact at the level of the Golgi and that Sort1 directs Shh away from the pathways that promote its secretion
Theorising Disability: Beyond Common Sense
This article seeks to introduce the topic of disability to political theory via a discussion of some of the literature produced by disability theorists. The author argues that these more radical approaches conceptualise disability in ways that conflict with ‘common-sense’ notions of disability that tend to underpin political theoretical considerations of the topic. Furthermore, the author suggests that these more radical conceptualisations have profound implications for current debates on social justice, equality and citizenship that highlight the extent to which these notions are also currently underpinned by ‘common-sense’ notions of ‘normality’
Subtraction Terms for Hadronic Production Processes at Next-to-Next-to-Leading Order
I describe a subtraction scheme for the next-to-next-to-leading order
calculation of single inclusive production at hadron colliders. Such processes
include Drell-Yan, W^{+/-}, Z and Higgs Boson production. The key to such a
calculation is a treatment of initial state radiation which preserves the
production characteristics, such as the rapidity distribution, of the process
involved. The method builds upon the Dipole Formalism and, with proper
modifications, could be applied to deep inelastic scattering and e^+ e^-
annihilation to hadrons.Comment: 4 page
Seminal magnetic fields from Inflato-electromagnetic Inflation
We extend some previous attempts to explain the origin and evolution of
primordial magnetic fields during inflation induced from a 5D vacuum. We show
that the usual quantum fluctuations of a generalized 5D electromagnetic field
cannot provide us with the desired magnetic seeds. We show that special fields
without propagation on the extra non-compact dimension are needed to arrive to
appreciable magnetic strengths. We also identify a new magnetic tensor field
in this kind of extra dimensional theories. Our results are in very
good agreement with observational requirements, in particular from TeV Blazars
and CMB radiation limits we obtain that primordial cosmological magnetic fields
should be close scale invariance.Comment: Improved version. arXiv admin note: text overlap with arXiv:1007.3891
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