Gain without population inversion in V-type systems driven by a frequency-modulated field

We obtain gain of the probe field at multiple frequencies in a closed three-level V-type system using frequency modulated pump field. There is no associated population inversion among the atomic states of the probe transition. We describe both the steady-state and transient dynamics of this system. Under suitable conditions, the system exhibits large gain simultaneously at series of frequencies far removed from resonance. Moreover, the system can be tailored to exhibit multiple frequency regimes where the probe experiences anomalous dispersion accompanied by negligible gain-absorption over a large bandwidth, a desirable feature for obtaining superluminal propagation of pulses with negligible distortion.Comment: 10 pages + 8 figures; To appear in Physical Review

Driving the atom by atomic fluorescence: analytic results for the power and noise spectra

We study how the spectral properties of resonance fluorescence propagate through a two-atom system. Within the weak-driving-field approximation we find that, as we go from one atom to the next, the power spectrum exhibits both sub-natural linewidth narrowing and large asymmetries while the spectrum of squeezing narrows but remains otherwise unchanged. Analytical results for the observed spectral features of the fluorescence are provided and their origin is thoroughly discussed.Comment: 13 pages, 5 figures; to be published in Phys. Rev. A Changed title and conten

Transformations in network governance: the case of migration intermediaries

types: Article"This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Ethnic and Migration Studies on 3 February 2015 available online: http://wwww.tandfonline.com/10.1080/1369183X.2014.1003803Market liberalisation has fundamentally changed state interventions in the supply of services and supportive infrastructure across a range of public services. While this trend has been relatively well documented, there has been a dearth of research into the changing nature of state interventions in migration and mobility. Indeed the increasing presence of migration intermediaries to service the many and varied needs of migrant workers, particularly skilled migrants, remains significantly under-researched both theoretically and empirically. In providing an analysis of the location, role and changing nature of migration intermediaries, we highlight the implications of commercially-driven governance structures. In particular we suggest that the shift from government to network governance has important implications for skilled migration including: inequities in access to information regarding the process of migration and labour market integration; and, greater dependence on (largely unregulated) private intermediaries. Accordingly, we present empirical examples of migration intermediaries to illustrate their role and the relationship with and implications of their exchange with migrants

Building inclusive nations in the age of migration

This is an Accepted Manuscript of an article published by Taylor & Francis in Identities: Global Studies in Culture and Power on 06 Apr 2016, available online: http://dx.doi.org/10.1080/1070289X.2016.1148607Nation and diversity are often casted in oppositional terms. The present joint-intervention explores the limits and possibilities of what we call ‘inclusive nation’, i.e. a nation which embraces rather than expunging diversity. To reflect on this idea, the Loughborough University Nationalism Network (LUNN) organized a symposium, bringing together both academics and relevant stakeholders, to explore both theoretically and practically the feasibility of the inclusive nation. For reason of space, here we present only the theoretical views of academics. While Billig and Yuval-Davis highlight the inherent exclusive thrust of nationalism, Kaufmann and Hearn suggest two distinct ways to move away the traditional understanding of nationalism as a site of singularity, oppression and exclusion. A final rejoinder by Nyhagen pushes the debate further interrogating the boundaries of national belonging

Sending money home: a mixed-Methods study of remittances by migrant nurses in Ireland

© 2009 Humphries et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

A reference human induced pluripotent stem cell line for large-scale collaborative studies

Human induced pluripotent stem cell (iPSC) lines are a powerful tool for studying development and disease, but the considerable phenotypic variation between lines makes it challenging to replicate key findings and integrate data across research groups. To address this issue, we sub-cloned candidate human iPSC lines and deeply characterized their genetic properties using whole genome sequencing, their genomic stability upon CRISPR-Cas9-based gene editing, and their phenotypic properties including differentiation to commonly used cell types. These studies identified KOLF2.1J as an all-around well-performing iPSC line. We then shared KOLF2.1J with groups around the world who tested its performance in head-to-head comparisons with their own preferred iPSC lines across a diverse range of differentiation protocols and functional assays. On the strength of these findings, we have made KOLF2.1J and its gene-edited derivative clones readily accessible to promote the standardization required for large-scale collaborative science in the stem cell field

Latin American immigrants in Indianapolis: Perceptions of prejudice and discrimination

The article focuses on immigrants’ interactions with the Indiana natives, with emphasis in the city of Indianapolis and its suburbs. More specifically, this study aims at providing an understanding of the experiences of Latin American immigrants with special attention to perceptions of prejudice and discrimination and to feelings of social exclusion. A substantial proportion of Latin American immigrants interviewed indicated that they considered Indiana natives to be prejudiced and that they had personally experienced discrimination. The study reveals specific examples of discrimination experienced by the immigrants at the work place, in housing, in stores, restaurants and by various service providers. The results of the study demonstrate the relevance of the normative and power resource theories to explain prejudice and discrimination

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe