Anti-vortex dynamics in magnetic nanostripes

In a thin magnetic nanostripe, an anti-vortex nucleates inside a moving domain wall when driven by an in-plane magnetic field greater than the so-called Walker field. The nucleated anti-vortex must cross the width of the nanostripe before the domain wall can propagate again, leading to low average domain wall speeds. A large out-of-plane magnetic field, applied perpendicularly to the plane of the nanostripe, inhibits the nucleation of the anti-vortex leading to fast domain wall speeds for all in-plane driving fields. We present micromagnetic simulation results relating the anti-vortex dynamics to the strength of the out-of-plane field. An asymmetry in the motion is observed which depends on the alignment of the anti-vortex core magnetic moments to the direction of the out-of-plane field. The size of the core is directly related to its crossing speed, both depending on the strength of the perpendicular field and the alignment of the core moments and direction of the out-of-plane field.Comment: 10 pages, 3 figure

Organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium or azolium enolates

This tutorial review highlights the organocatalytic Lewis base functionalisation of carboxylic acids, esters and anhydrides via C1-ammonium/azolium enolates. The generation and synthetic utility of these powerful intermediates is highlighted through their application in various methodologies including aldol-lactonisations, Michael-lactonisations/lactamisations and [2,3]-rearrangements.Publisher PDFPeer reviewe

Measurement of Non-Market Output in Education and Health

In recent years considerable progress has been made in developing improved methodologies to measure non-market output in the National Accounts. Most EU Member States have supported the introduction of a legal framework to implement these methodologies and have introduced current best practice methods to measure output of health and education services. This report summarises contributions at a Workshop held in October 2006 that focussed on building on this foundation and further improving the measurement of non-market output in the National Accounts. The Workshop supports a project intended to provide detailed international guidelines for the further development of volume measures of non-market outputs, in particular for education and health.

Antivortex Dynamics in Magnetic Nanostripes

In a thin magnetic nanostripe, an antivortex nucleates inside a moving domain wall when driven by an in-plane magnetic field greater than the so-called Walker field. The nucleated antivortex must cross the width of the nanostripe before the domain wall can propagate again, leading to low average domain wall speeds. A large out-of-plane magnetic field, applied perpendicularly to the plane of the nanostripe, inhibits the nucleation of the antivortex leading to fast domain wall speeds for all in-plane driving fields. We present micromagnetic simulation results relating the antivortex dynamics to the strength of the out-of-plane field. An asymmetry in the motion is observed which depends on the alignment of the antivortex core magnetic moments to the direction of the out-of-plane field. The size of the core is directly related to its crossing speed, both depending on the strength of the perpendicular field and the alignment of the core moments and direction of the out-of-plane field

Mamluk Jerusalem: Architecturally Challenging Narratives

Narratives abound concerning the religious and political positioning of Jerusalem in the past as well as the present and have been used in a variety of ways to serve various ideologies or political ends. One such narrative (which can be found even in some academic treatises of the history of Jerusalem) states that following the Muslim re-conquest of the city after the Crusades Muslim rulers neglected the city entirely, leading to its decline into obscurity and ruin. This narrative asserts that the city remained as such until Zionism, Jewish immigration, and, most especially, the establishment of the state of Israel rescued Jerusalem and resituated it in its preeminent position as the Holy City. This paper argues against such a narrative by examining the architectural contributions and growth of the city religiously during the rule of the Mamluk Empire (1250-1517). While it is true that in some ways the political prestige of Jerusalem waned under the Muslim rule of this time, it’s religious importance grew beyond what it had seen prior to the Crusades. This will be illustrated by a discussion of certain political and religious factors and practices that influenced the development of the city, as well as a discussion of several examples of buildings and structures that illustrate the extent to which the Mamluks prized the city and were interested in both its growth and prestige in religious, albeit not political, terms

Rubisco evolution in C4 eudicots: an analysis of Amaranthaceae sensu lato

BACKGROUND Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyses the key reaction in the photosynthetic assimilation of CO₂. In C₄ plants CO₂ is supplied to Rubisco by an auxiliary CO₂-concentrating pathway that helps to maximize the carboxylase activity of the enzyme while suppressing its oxygenase activity. As a consequence, C₄ Rubisco exhibits a higher maximum velocity but lower substrate specificity compared with the C₃ enzyme. Specific amino-acids in Rubisco are associated with C₄ photosynthesis in monocots, but it is not known whether selection has acted on Rubisco in a similar way in eudicots. METHODOLOGY/PRINCIPAL FINDINGS We investigated Rubisco evolution in Amaranthaceae sensu lato (including Chenopodiaceae), the third-largest family of C₄ plants, using phylogeny-based maximum likelihood and Bayesian methods to detect Darwinian selection on the chloroplast rbcL gene in a sample of 179 species. Two Rubisco residues, 281 and 309, were found to be under positive selection in C₄ Amaranthaceae with multiple parallel replacements of alanine by serine at position 281 and methionine by isoleucine at position 309. Remarkably, both amino-acids have been detected in other C₄ plant groups, such as C₄ monocots, illustrating a striking parallelism in molecular evolution. CONCLUSIONS/SIGNIFICANCE Our findings illustrate how simple genetic changes can contribute to the evolution of photosynthesis and strengthen the hypothesis that parallel amino-acid replacements are associated with adaptive changes in Rubisco.This research was funded by NERC (http://www.nerc.ac.uk/; grant number NE/H007741/1)