Coherent Interaction of a Single Fermion with a Small Bosonic Field

We have experimentally studied few-body impurity systems consisting of a single fermionic atom and a small bosonic field on the sites of an optical lattice. Quantum phase revival spectroscopy has allowed us to accurately measure the absolute strength of Bose-Fermi interactions as a function of the interspecies scattering length. Furthermore, we observe the modification of Bose-Bose interactions that is induced by the interacting fermion. Because of an interference between Bose-Bose and Bose-Fermi phase dynamics, we can infer the mean fermionic filling of the mixture and quantify its increase (decrease) when the lattice is loaded with attractive (repulsive) interspecies interactions.Comment: 4+ pages, 5 figures, updated to <a href="http://dx.doi.org/10.1103/PhysRevLett.106.115305">published version</a

Quaker Events for Young People: Informal Education and Faith Transmission

This article examines Quaker events for young people and explores the nature of these events through examination of official policies, questionnaires and observation at events. It examines the purposes of Quaker events for young people as described by official policies and by youth work practitioners and examines the significance of these events in the lives of adolescent Quakers. Quaker events for young people are analysed in comparison with the values and principles of \u27informal education\u27. Contrasts are drawn between Quaker events for young people and Christian youth work. This article also explores the nature of faith transmission at Quaker events for young people and argues that Quaker events for young people are the most effective method of faith transmission for adolescent Quakers

Adolescent Quakers: A Hidden Sect?

This paper uses British Quakers as a case study to illustrate how very different perspectives on group identity pertain between the adult group and Quaker youth. While the older Quakers see the young Quakers as a part of \u27their\u27 group, the adolescents do not feel the same level of affinity with older Quakers. This paper examines the sectarian nature of both groups and argues that while both groups have sect-like characteristics the sectarian nature of the two groups is differently configured. It argues that the adult group fa ils to acknowledge the adolescent group as a separate sect within the sect which results in it remaining hidden to all but its own members and ensures its continuing cultural, institutional and theological marginalisation. This paper argues that the study of youth and religion can be confused by scholars who misread the nature of the relationship between the youth and their \u27parent\u27 church

The complex concept of sustainable of diversity management:…and why forming policies in this area is far from straightforward

Purpose – Explores the notion of sustainable diversity-management practices. Design/methodology/approach – Summarizes research into the sustainability of diversity management across four countries and provides examples of efforts to maintain high levels of diversity. Findings – Looks at the activities of Africa House, an organization that develops business links with Africa, and of BEN Television, which is a television station that caters primarily for ethnic minorities. Practical implications – Demonstrates that diversity is a multi-dimensional concept that can be structured within two frameworks: demographic diversity regarding, for example, age, gender and nationality; and human-capital diversity, such as cognitive diversity, skill and experience diversity. Social implications – Highlights the complexity of diversity and so the difficulty of legislating in this area. Originality/value – Explains that employees can also stifle attempts to engage in sustainable diversity management policies. A lack of understanding of local laws or language, or through limited social contacts, can prevent full participation by employees

Radio loud AGN and the L_X - \sigma relation of galaxy groups and clusters

We use the ROSAT All-Sky Survey to study the X-ray properties of a sample of 625 groups and clusters of galaxies selected from the Sloan Digital Sky Survey. We stack clusters with similar velocity dispersions and investigate whether their average X-ray luminosities and surface brightness profiles vary with the radio activity level of their central galaxies. We find that at a given value of $\sigma$, clusters with a central radio AGN have more concentrated X-ray surface brightness profiles, larger central galaxy masses, and higher X-ray luminosities than clusters with radio-quiet central galaxies. The enhancement in X-ray luminosity is more than a factor of two, is detected with better than 6$\sigma$ significance, and cannot be explained by X-ray emission from the radio AGN itself. This difference is largely due to a subpopulation of radio-quiet, high velocity dispersion clusters with low mass central galaxies. These clusters are underluminous at X-ray wavelengths when compared to otherwise similar clusters where the central galaxy is radio-loud, more massive, or both.Comment: Section 5.2 is updated, more discussion on the dependence of L_X - \sigma relation on the stellar mass of BCG

Evolution of the Most Massive Galaxies to z ~ 0.6: II. The link between radio AGN activity and star formation

We analyze the optical spectra of massive (log M*/Msun > 11.4) radio-loud galaxies at z~0.2 and z~0.6. By comparing stellar population parameters of these radio-loud samples with radio-quiet control samples, we investigate how the presence of a radio-emitting jet relates to the recent star formation history of the host galaxy. We also investigate how the emission-line properties of the radio galaxies evolve with redshift by stacking their spectra. Our main results are the following. (1) Both at low and at high redshift, half as many radio-loud as radio-quiet galaxies have experienced significant star formation in the past Gyr. (2) The Balmer absorption line properties of massive galaxies that have experienced recent star formation show that star formation occurred as a burst in many of these systems. (3) Both the radio and the emission-line luminosity of radio AGN evolve significantly with redshift. However, radio galaxies with similar stellar population parameters, have similar emission-line properties both at high- and at low-redshift. These results suggest that massive galaxies experience cyclical episodes of gas accretion, star formation and black hole growth, followed by the production of a radio jet that shuts down further activity. The behaviour of galaxies with log M*/Msun > 11.4 is the same at z = 0.6 as it is at z = 0.2, except that higher redshift galaxies experience more star formation and black hole growth and produce more luminous radio jets during each accretion cycle.Comment: 14 pages, 12 figures, submitted to MNRA

Collagen fibre implant for tendon and ligament biological augmentation. In vivo study in an ovine model.

PURPOSE: Although most in vitro studies indicate that collagen is a suitable biomaterial for tendon and ligament tissue engineering, in vivo studies of implanted collagen for regeneration of these tissues are still lacking. The objectives of this study were the following: (1) to investigate the regeneration of the central third of the ovine patellar tendon using implants made of an open array of collagen fibres (reconstituted, extruded bovine collagen); and (2) to compare two collagen crosslinking chemistries: carbodiimide and carbodiimide associated with ethyleneglycoldiglycidylether. METHODS: Forty-eight Welsh Mountain sheep were operated on their right hind leg. The central third of patellar tendon was removed and substituted with carbodiimide (n = 16) and carbodiimide-ethyleneglycoldiglycidylether-crosslinked implants (n = 16). In the control group the defect was left empty (n = 16). The central third of contralateral unoperated tendons was used as positive controls. Half of the sheep in each group were killed at 3- and 6-month time points. After proper dissection, tendon sub-units (medial, central and lateral) were tested to failure (n = 6 for each group), whilst 2 non-dissected samples were used for histology. RESULTS: Both the implants had significantly lower stress to failure and modulus with respect to native tendon at both 3- and at 6-month time points. The implants did not statistically differ in stress to failure, whilst carbodiimide-crosslinked implants had significantly higher modulus than carbodiimide-ethyleneglycoldiglycidylether-crosslinked implants both at 3 and at 6 months. Histology showed carbodiimide-crosslinked implants to have a better integration with the native tendon than carbodiimide-ethyleneglycoldiglycidylether-crosslinked implants. Carbodiimide-crosslinked implants appeared partially resorbed and showed increased tissue ingrowth with respect to carbodiimide-ethyleneglycoldiglycidylether-crosslinked implants. CONCLUSIONS: To deliver collagen implants as an open array of fibres allows optimal tendon-implant integration and good ingrowth of regenerated tissue. In the present study the resorption rate of both the examined implants was too low due to the high level of crosslinking. This led to only minor substitution of the implant with regenerated tissue, which in turn produced a low-strength implanted region. Further studies are needed to find the right balance between strength and resorption rate of collagen fibres