Magnetic impurity resonance states and symmetry of the superconducting order parameter in iron-based superconductors

We investigate the effect of magnetic impurities on the local quasiparticle density of states (LDOS) in iron-based superconductors. Employing the two-orbital model where 3$d$ electron and hole conduction bands are hybridizing with the localized $f$-orbital of the impurity spin, we investigate how various symmetries of the superconducting gap and its nodal structure influence the quasiparticle excitations and impurity bound states. We show that the bound states behave qualitatively different for each symmetry. Most importantly we find that the impurity-induced bound states can be used to identify the nodal structure of the extended s-wave symmetry ($S^{\pm}$) that is actively discussed in ferropnictides.Comment: 7 pages, 5 figures, theory part is extended, figures are replace

Determination of the crystal structure of CuSnTi by full profile Rietveld analysis

The crystal structure of the new ternary phase CuSnTi is determined by full profile Rietveld analysis of the powder diffractogram. 104 reflections were refined to a final RBragg value of 5.60%. CuSnTi crystallizes with the spacegroup P63/mmc and is isostructural to InNi2. The lattice parameters are a=0.439 555(5) nm and c=0.601 505(9) n

Secret seducers - True tales of pimps in the red light district of Amsterdam

At the end of the 1990s, a moral panic erupted in the Netherlands about the phenomenon of what came to be known as 'loverboys'. The suspicion was that a growing number of Dutch girls were being groomed by handsome young men who employed all sorts of devious methods to prepare their girlfriends for life as a prostitute. Stories about a new generation of pimps, often of Moroccan origin, regularly appeared in the Dutch media. In this article, based on ethnographic fieldwork on pimps operating in the red-light district of Amsterdam, we describe the ways in which these young men operate and how they justify their behaviour. On the basis of empirical research we intend to present a more realistic picture of what goes on in the prostitution industry and highlight the discrepancy between what is reported in the media and what is actually happening in the prostitution sector. We also examine the background to the moral panic about loverboys and the ways in which these young men were supposedly able to induce many young girls into becoming prostitutes

Experiencing stigma as sex work researchers in professional and personal lives

Researchers have demonstrated the challenges associated with sex work research; negotiating the stigma attached to its subject matter, the perceived dangerousness of participants, and the barriers faced in reaching hidden populations. By reflecting upon our separate research experiences and drawing upon a body of reflexive sex work research, this article explores how, as sex work researchers, we experienced stigma not only in our professional roles as researchers, but also in our personal lives. We apply Goffman's (1968) notion of stigma by association; and consider how stigma often associated with prostitution became transposed onto us. In particular, we compare and contrast our separate experiences of conducting sex work research to demonstrate our similar experiences of stigma by association

Assembly defects of human tRNA splicing endonuclease contribute to impaired pre-tRNA processing in pontocerebellar hypoplasia

Mutations within subunits of the tRNA splicing endonuclease complex (TSEN) are associated with pontocerebellar hypoplasia (PCH). Here the authors show that tRNA intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers, and provide evidence that modulation of TSEN stability may contribute to PCH phenotypes.Introns of human transfer RNA precursors (pre-tRNAs) are excised by the tRNA splicing endonuclease TSEN in complex with the RNA kinase CLP1. Mutations in TSEN/CLP1 occur in patients with pontocerebellar hypoplasia (PCH), however, their role in the disease is unclear. Here, we show that intron excision is catalyzed by tetrameric TSEN assembled from inactive heterodimers independently of CLP1. Splice site recognition involves the mature domain and the anticodon-intron base pair of pre-tRNAs. The 2.1-angstrom resolution X-ray crystal structure of a TSEN15-34 heterodimer and differential scanning fluorimetry analyses show that PCH mutations cause thermal destabilization. While endonuclease activity in recombinant mutant TSEN is unaltered, we observe assembly defects and reduced pre-tRNA cleavage activity resulting in an imbalanced pre-tRNA pool in PCH patient-derived fibroblasts. Our work defines the molecular principles of intron excision in humans and provides evidence that modulation of TSEN stability may contribute to PCH phenotypes.Genetics of disease, diagnosis and treatmen

Performing Amateurism: A Study of Camgirls’ Work

International audienc

“The Good into the Pot, the Bad into the Crop!”—A New Technology to Free Stem Cells from Feeder Cells

A variety of embryonic and adult stem cell lines require an intial co-culturing with feeder cells for non-differentiated growth, self renewal and maintenance of pluripotency. However for many downstream ES cell applications the feeder cells have to be considered contaminations that might interfere not just with the analysis of experimental data but also with clinical application and tissue engineering approaches. Here we introduce a novel technique that allows for the selection of pure feeder-freed stem cells, following stem cell proliferation on feeder cell layers. Complete and reproducible separation of feeder and embryonic stem cells was accomplished by adaptation of an automated cell selection system that resulted in the aspiration of distinct cell colonies or fraction of colonies according to predefined physical parameters. Analyzing neuronal differentiation we demonstrated feeder-freed stem cells to exhibit differentiation potentials comparable to embryonic stem cells differentiated under standard conditions. However, embryoid body growth as well as differentiation of stem cells into cardiomyocytes was significantly enhanced in feeder-freed cells, indicating a feeder cell dependent modulation of lineage differentiation during early embryoid body development. These findings underline the necessity to separate stem and feeder cells before the initiation of in vitro differentiation. The complete separation of stem and feeder cells by this new technology results in pure stem cell populations for translational approaches. Furthermore, a more detailed analysis of the effect of feeder cells on stem cell differentiation is now possible, that might facilitate the identification and development of new optimized human or genetically modified feeder cell lines

Does it look safe? An eye tracking study into the visual aspects of fear of crime

Studies of fear of crime often focus on demographic and social factors, but these can be difficult to change. Studies of visual aspects have suggested that features reflecting incivilities, such as litter, graffiti, and vandalism increase fear of crime, but methods often rely on participants actively mentioning such aspects, and more subtle, less conscious aspects may be overlooked. To address these concerns, the present study examined people’s eye movements while they judged scenes for safety. Forty current and former university students were asked to rate images of day-time and night-time scenes of Lincoln, UK (where they studied) and Egham, UK (unfamiliar location) for safety, maintenance and familiarity, while their eye movements were recorded. Another twenty-five observers not from Lincoln or Egham rated the same images in an internet survey. Ratings showed a strong association between safety and maintenance and lower safety ratings for night-time scenes for both groups, in agreement with earlier findings. Eye movements of the Lincoln participants showed increased dwell times on buildings, houses, and vehicles during safety judgments, and increased dwell times on streets, pavements, and markers of incivilities for maintenance. Results confirm that maintenance plays an important role in perceptions of safety, but eye movements suggest that observers also look for indicators of current or recent presence of people