Search results for "VARIATION"
showing 10 items of 2124 documents
African trypanosomes expressing multiple VSGs are rapidly eliminated by the host immune system
2019
Significance Many parasites escape the host immune system by undergoing antigenic variation, a process in which surface antigens are regularly shed and replaced by new ones. Trypanosoma brucei employs multiple sophisticated molecular mechanisms to ensure the expression of a homogeneous VSG coat. We generated a mutant parasite that expresses multiple distinct VSGs and studied the consequences of having a multi-VSG coat during an infection. We showed that expression of multiple VSGs makes the parasites more vulnerable to the immune response, which can now control the trypanosomes from the onset of the infection, allowing most mice to survive. In the future, trypanosome infections may be treat…
Mayors in the Town Hall: Patterns of Relations and Conflict Among Municipal Actors
2017
The chapter explores the way in which local actors interrelate with each other and the environment surrounding them. For doing so, it analyses the balance of power among municipal actors in European town halls and to what extent these relationships are characterised either by consensus or by conflict. The findings confirm the existence of differences among types of government, confirming the validity of the Mourtizen–Svara’s typology to capture the division of functions at the apex of local leadership forms of local government. When analysing the level of conflict, other factors such as the level of local autonomy in the political system, the municipality’s economic situation or the mayor’s…
Patterns of variation in tail ornament size in birds
1988
In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua, the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi (‘heterogony’ with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (av…
A 4500 year record of palaeomagnetic secular variation and relative palaeointensity from the Tyrrhenian Sea
2020
A marine sediment core from the western Mediterranean provides a newhigh-resolution 4,500-year record of palaeomagnetic secular variation and relativepalaeointensity. In 2013, the 7.1-metre C5 core was recovered from the TyrrhenianSea as part of the NextData climate data project. The coring site, 15 km offshorefrom the Volturno river mouth, is well-located to record combined marine andterrestrial palaeoclimatic influences, and the fine-grained, rapidly deposited sedimentsare effective palaeomagnetic recorders. We investigate the palaeomagnetic field direction and strength recorded in the core, which provide a valuable high-resolution recordof Holocene geomagnetic variation in the area. Usin…
When is Architecture Not Design?
2019
If there’s nothing more to architecture than design, and to its attendant thinking processes than design thinking, then core dimensions of the enterprise from production and use angles have no special character over and above their counterparts in general design. Yet that does not appear to be true by the lights of architects or design specialists or the public at large. So what is it, at the core or periphery of the discipline or its objects, that makes architecture not design? The ways in which architecture and design constitute artistic enterprises, drawing on and promoting aesthetic interest, differ such that architecture is not, or at least not only, a branch of or variation on desi…
Identifying gene-environment interactions in schizophrenia: contemporary challenges for integrated, large-scale investigations
2014
European Community Recent years have seen considerable progress in epidemiological and molecular genetic research into environmental and genetic factors in schizophrenia, but methodological uncertainties remain with regard to validating environmental exposures, and the population risk conferred by individual molecular genetic variants is small. There are now also a limited number of studies that have investigated molecular genetic candidate gene-environment interactions (G x E), however, so far, thorough replication of findings is rare and G x E research still faces several conceptual and methodological challenges. in this article, we aim to review these recent developments and illustrate h…
Solutions to the 1-harmonic flow with values into a hyper-octant of the N-sphere
2013
Abstract We announce existence results for the 1-harmonic flow from a domain of R m into the first hyper-octant of the N -dimensional unit sphere, under homogeneous Neumann boundary conditions. The arguments rely on a notion of “geodesic representative” of a BV-vector field on its jump set.
THE 1-HARMONIC FLOW WITH VALUES IN A HYPEROCTANT OF THE N-SPHERE
2014
We prove the existence of solutions to the 1-harmonic flow — that is, the formal gradient flow of the total variation of a vector field with respect to the [math] -distance — from a domain of [math] into a hyperoctant of the [math] -dimensional unit sphere, [math] , under homogeneous Neumann boundary conditions. In particular, we characterize the lower-order term appearing in the Euler–Lagrange formulation in terms of the “geodesic representative” of a BV-director field on its jump set. Such characterization relies on a lower semicontinuity argument which leads to a nontrivial and nonconvex minimization problem: to find a shortest path between two points on [math] with respect to a metric w…
Study of USH1 Splicing Variants through Minigenes and Transcript Analysis from Nasal Epithelial Cells
2012
Usher syndrome type I (USH1) is an autosomal recessive disorder characterized by congenital profound deafness, vestibular areflexia and prepubertal retinitis pigmentosa. The first purpose of this study was to determine the pathologic nature of eighteen USH1 putative splicing variants found in our series and their effect in the splicing process by minigene assays. These variants were selected according to bioinformatic analysis. The second aim was to analyze the USH1 transcripts, obtained from nasal epithelial cells samples of our patients, in order to corroborate the observed effect of mutations by minigenes in patient’s tissues. The last objective was to evaluate the nasal ciliary beat fre…
Macro-elements in the mixed boundary value problems
2000
The symmetric Galerkin boundary element method (SGBEM), applied to elastostatic problems, is employed in defining a model with BE macro-elements. The model is governed by symmetric operators and it is characterized by a small number of independent variables upon the interface between the macro-elements.