Interaction between current imbalance and magnetization in LHC cables

The quality of the magnetic field in superconducting accelerator magnets is associated with the properties of the superconducting cable. Current imbalances due to coupling currents ¿I, as large as 100 A, are induced by spatial variations of the field sweep rate and contact resistances. During injection at a constant field all magnetic field components show a decay behavior. The decay is caused by a diffusion of coupling currents into the whole magnet. This results in a redistribution of the transport current among the strands and causes a demagnetization of the superconducting cable. As soon as the field is ramped up again after the end of injection, the magnetization rapidly recovers from the decay and follows the course of the original hysteresis curve. In order to clarify the interactions between the changes in current and magnetization during injection the authors performed a number of experiments. A magnetic field with a spatially periodic pattern was applied to a superconducting wire in order to simulate the coupling behavior in a magnet. This model system was placed into a stand for magnetization measurements and the influence of different powering conditions was analyze

The evolution of early-life effects on social behaviour-why should social adversity carry over to the future?

Numerous studies have shown that social adversity in early life can have long-lasting consequences for social behaviour in adulthood, consequences that may in turn be propagated to future generations. Given these intergenerational effects, it is puzzling why natural selection might favour such sensitivity to an individual's early social environment. To address this question, we model the evolution of social sensitivity in the development of helping behaviours, showing that natural selection indeed favours individuals whose tendency to help others is dependent on early-life social experience. In organisms with non-overlapping generations, we find that natural selection can favour positive social feedbacks, in which individuals who received more help in early life are also more likely to help others in adulthood, while individuals who received no early-life help develop low tendencies to help others later in life. This positive social sensitivity is favoured because of an intergenerational relatedness feedback: patches with many helpers tend to be more productive, leading to higher relatedness within the local group, which in turn favours higher levels of help in the next generation. In organisms with overlapping generations, this positive feedback is less likely to occur, and those who received more help may instead be less likely to help others (negative social feedback). We conclude that early-life social influences can lead to strong between-individual differences in helping behaviour, which can take different forms dependent on the life history in question. This article is part of the theme issue 'Developing differences: early-life effects and evolutionary medicine'

The Pricing Of Petroleum Products In Pakistan

In Pakistan the prices of petroleum products are set by the government, to raise revenues, stabilize prices, and achieve redistribution and social objectives. But in addition to these benefits, government31 taxes and subsidies for petroleum pro• ducts result in losses in economic efficiency through the misallocation of resources. How do the benefits compare with these losses? Are revenues raised in a manner that minimizes economic waste? Do the subsidies achieve equity or other social benefits at minimum cost

Sexual selection in bacteria?

This is the final version. Available from the publisher via the DOI in this record.A main mechanism of lateral gene transfer in bacteria is transformation, where cells take up free DNA from the environment which subsequently can be recombined into the genome. Bacteria are also known to actively release DNA into the environment through secretion or lysis, which could aid uptake via transformation. Various evolutionary benefits of DNA uptake and DNA release have been proposed but these have all been framed in the context of natural selection. Here, we interpret bacterial DNA uptake and release in the context of sexual selection theory, which has been central to our understanding of the bewildering diversity of traits associated with sexual reproduction in the eukaryote world but has never been applied to prokaryotes. Specifically, we explore potential scenarios where bacteria releasing DNA into the environment could compete for successful uptake by other cells, or where bacteria could selectively take up DNA to enhance their fitness. We conclude that there is potential for sexual selection to act in bacteria, and that this might in part explain the considerable diversity in transformation-related behaviours.Royal SocietyNatural Environment Research Council (NERC

Missionland, a multinational co-operation program to construct and share a generic mission simulation environment

A simulation environment is a virtual representation of the real-world natural and cultural environment. Such an environment contains dynamic elements, for example weather, time of day and moving vehicles, as well as static elements, for example vegetation, buildings and infrastructure. When performing distributed (joint) simulations a number of problems exist concerning the selection and use of a simulation environment. These problems can either be caused by the different requirements of the participating users or by different technical capabilities. As training via distributed mission simulation has the potential to enhance force readiness and operational effectiveness in coalition operations, these problems with the environment representation should be solved. Normally, this can be done by correlating existing environment databases, but that is costly, both in effort and in money, and the end-result will always be hampered by technical incompatibilities. It also does not address security and political limitations. Therefore it is preferable to create a generic and geo-unspecific simulation environment, Missionland

Degaussing and Decay Reduction in the Short Superconducting Dipole Models for the LHC

The time decay of field harmonics during current plateaus is a known drawback of superconducting accelerator magnets. The present understanding of this phenomenon refers to a combination of flux creep and of the interaction between the redistribution of currents in Rutherford cables and the filament magnetization. Current cycles of decreasing amplitude, called here degaussing, were found to reduce significantly the decay observed in accelerator magnets. This paper reports on the measured reduction of decay obtained in short dipole models for the LHC and on one experiment with a single LHC strand

Children's Pronoun Interpretation Problems Are Related to Theory of Mind and Inhibition, But Not Working Memory

In several languages, including English and Dutch, children’s acquisition of the interpretation of object pronouns (e.g., him) is delayed compared to that of reflexives (e.g., himself). Various syntactic and pragmatic explanations have been proposed to account for this delay in children’s acquisition of pronoun interpretation. This study aims to provide more insight into this delay by investigating potential cognitive mechanisms underlying this delay. Dutch-speaking children between 6 and 12 years old with autism spectrum disorder (ASD; n = 47), attention-deficit/hyperactivity disorder (ADHD; n = 36) or typical development (TD; n = 38) were tested on their interpretation and production of object pronouns and reflexives and on theory of mind, working memory, and response inhibition. It was found that all three groups of children had difficulty with pronoun interpretation and that their performance on pronoun interpretation was associated with theory of mind and inhibition. These findings support an explanation of object pronoun interpretation in terms of perspective taking, according to which listeners need to consider the speaker’s perspective in order to block coreference between the object pronoun and the subject of the same sentence. Unlike what is predicted by alternative theoretical accounts, performance on pronoun interpretation was not associated with working memory, and the children made virtually no errors in their production of object pronouns. As the difficulties with pronoun interpretation were similar for children with ASD, children with ADHD and typically developing children, this suggests that certain types of perspective taking are unaffected in children with ASD and ADHD

Thermal Conductivity of Structural Glass/Fibre Epoxy Composite as a Function of Fibre Orientation

The LHC, the new superconducting particle accelerator presently under construction at CERN, makes use of some 1200 dipole magnets for orbit bending and 500 quadrupole magnets for focusing/defocusing of the circulating high-energy proton beams. Two or three column-type support posts sustain each cryomagnet. The choice of a convenient material for these supports is critical, because of the required high positioning accuracy of the magnets in their cryostats and stringent thermal budget requirements imposed by the LHC cryogenic system. A glass-fibre/epoxy resin composite has been chosen for its good combination of high stiffness and low thermal conductivity over the 2-293 K temperature range. Plies of long glass-fibres are stacked optimally yielding the best mechanical behaviour. However, heat leaks from the supports are influenced by the thermal characteristics of the composite, which in turn depend on the orientation of the fibres. To study the dependence of the thermal conductivity on fibre's orientation, we performed high precision thermal conductivity measurements of various samples of glass-fibre/epoxy resin composite. The results of the thermal conductivity measurements are compared with integral measurements on support posts for LHC cryomagnets and with mixing models

Ecological genetic conflict: Genetic architecture can shift the balance between local adaptation and plasticity

This is the author accepted manuscript. The final version is available from University of Chicago Press via the DOI in this record.Genetic polymorphism can contribute to local adaptation in heterogeneous habitats, for instance as a single locus with alleles adapted to different habitats. Phenotypic plasticity can also contribute to trait variation across habitats, through developmental responses to habitat-specific cues. We show that the genetic architecture of genetically polymorphic and plasticity loci may influence the balance between local adaptation and phenotypic plasticity. These effects of genetic architecture are instances of ecological genetic conflict. A reduced effective migration rate for genes tightly linked to a genetic polymorphism provides an explanation for the effects, and they can occur both for a single trait and for a syndrome of co-adapted traits. Using individualbased simulations and numerical analysis, we investigate how among-habitat genetic polymorphism and phenotypic plasticity depend on genetic architecture. We also study the evolution of genetic architecture itself, in the form of rates of recombination between genetically polymorphic loci and plasticity loci. Our main result is that for plasticity genes that are unlinked to loci with between-habitat genetic polymorphism, the slope of a reaction norm is steeper in comparison with the slope favored by plasticity genes that are tightly linked to genes for local adaptation.This work was supported by grants from the Carl Trygger Foundation (CTS 15292) to OL and by a Leverhulme Trust International Network Grant to SRXD, PH, OL, and JMM