771 research outputs found
Differentiated embedding: Polish migrants in London Negotiating Belonging Over Time
Developing on Granovetter’s classic work on embeddedness in systems of social relations, this paper
proposes the concept of ‘differentiated embedding’ to explore how migrants negotiate attachment and belonging as
dynamic temporal, spatial and relational processes. When Poland joined the EU in May 2004 the large flow of migrants
to the UK was perceived by many migration researchers as heralding a new form of transient mobility associated with
short-term, temporary and circular migration, and high levels of transnationalism. Relatively little attention was paid
to how these migrants were integrating in local contexts.
Based on 20 in-depth interviews and network mapping with Polish migrants,resident in London for a decade, I examine
why participants extended their stay and how their decisions were shaped by inter-personal relationships locally and
transnationally. London as a ‘super-diverse’, global city offers place–specific opportunities for building networks and
developing processes of embedding. Nonetheless, a focus on networks risks overlooking the wider structural context
in which migrants live and work. Thus, I argue, there is a need for a differentiated concept to capture the nuanced
interplay of structural, relational, spatial and temporal embedding. This concept not only captures multi-scalarity and
multi-sectorality but also levels of belonging and attachment
Perceptions, prejudices and possibilities : young people narrating apprenticeship experiences
There is growing international interest in young people’s post-compulsory education pathways. In contexts of ‘widening participation’ as university is increasingly ‘normalised’, how do young people choose alternative routes into training and employment? While in Britain apprenticeships are a key aspect of government strategy, there are many challenges still associated with these schemes including low pay and inconsistent training. Drawing on longitudinal data from our qualitative research with young people on apprenticeship schemes in London, we use narrative analysis, informed by Goffman’s theory of stigma, to explore how young people narrate and navigate the tensions between apprenticeships as opportunities to ‘learn while they earn’, and university degrees
as the prevailing ‘gold standard’ of achievement and future success. Our findings show that while these young people were aware of the challenges associated with apprenticeships, they used specific rhetorical devices to reclaim the normalcy of
their training pathways as ‘sensible’ and ‘mature’ choices
Genetic characterization of flea-derived Bartonella species from native animals in Australia suggests host-parasite co-evolution
Fleas are important arthropod vectors for a variety of diseases in veterinary and human medicine, and bacteria belonging to the genus Bartonella are among the organisms most commonly transmitted by these ectoparasites. Recently, a number of novel Bartonella species and novel species candidates have been reported in marsupial fleas in Australia. In the present study the genetic diversity of marsupial fleas was investigated; 10 species of fleas were collected from seven different marsupial and placental mammal hosts in Western Australia including woylies (Bettongia penicillata), western barred bandicoots (Perameles bougainville), mardos (Antechinus flavipes), bush rats (Rattus fuscipes), red foxes (Vulpes vulpes), feral cats (Felis catus) and rabbits (Oryctolagus cuniculus). PCR and sequence analysis of the cytochrome oxidase subunit I (COI) and the 18S rRNA genes from these fleas was performed. Concatenated phylogenetic analysis of the COI and 18S rRNA genes revealed a close genetic relationship between marsupial fleas, with Pygiopsylla hilli from woylies, Pygiopsylla tunneyi from western barred bandicoots and Acanthopsylla jordani from mardos, forming a separate cluster from fleas collected from the placental mammals in the same geographical area. The clustering of Bartonella species with their marsupial flea hosts suggests co-evolution of marsupial hosts, marsupial fleas and Bartonella species in Australia
Material mapping of QCT-derived scapular models : a comparison with micro-CT loaded specimens using digital volume correlation
Subject- and site-specific modeling techniques greatly improve finite element models (FEMs) derived from clinical-resolution CT data. A variety of density-modulus relationships are used in scapula FEMs, but the sensitivity to selection of relationships has yet to be experimentally evaluated. The objectives of this study were to compare quantitative-CT (QCT) derived FEMs mapped with different density-modulus relationships and material mapping strategies to experimentally loaded cadaveric scapular specimens. Six specimens were loaded within a micro-CT (33.5 μm isotropic voxels) using a custom-hexapod loading device. Digital volume correlation (DVC) was used to estimate full-field displacements by registering images in pre- and post-loaded states. Experimental loads were measured using a 6-DOF load cell. QCT-FEMs replicated the experimental setup using DVC-driven boundary conditions (BCs) and were mapped with one of fifteen density-modulus relationships using elemental or nodal material mapping strategies. Models were compared based on predicted QCT-FEM nodal reaction forces compared to experimental load cell measurements and linear regression of the full-field nodal displacements compared to the DVC full-field displacements. Comparing full-field displacements, linear regression showed slopes ranging from 0.86 to 1.06, r-squared values of 0.82–1.00, and max errors of 0.039 mm for all three Cartesian directions. Nearly identical linear regression results occurred for both elemental and nodal material mapping strategies. Comparing QCT-FEM to experimental reaction forces, errors ranged from − 46 to 965% for all specimens, with specimen-specific errors as low as 3%. This study utilized volumetric imaging combined with mechanical loading to derive full-field experimental measurements to evaluate various density-modulus relationships required for QCT-FEMs applied to whole-bone scapular loading. The results suggest that elemental and nodal material mapping strategies are both able to simultaneously replicate experimental full-field displacements and reactions forces dependent on the density-modulus relationship used
Identification of novel trypanosome genotypes in native Australian marsupials
In the present study, the occurrence and molecular phylogeny of trypanosome parasites were studied in both wild and captive marsupials from Western Australia and Queensland. Blood samples were screened by PCR at the 18S rDNA locus, and the glycosomal glyceraldehyde phosphate dehydrogenase gene. Overall, 5.3% of the blood samples were positive at the 18S rDNA locus. All positives belonged to wild-captured Western Australian individuals, where trypanosome-specific DNA was detected in 9.8% of the screened samples from wild marsupials, in common brushtail possums, and woylies. The detection rate of trypanosome DNA in these two host species was 12.5% and 20%, respectively. Phylogenetic analyses based on two loci, indicated that the possum-derived trypanosome isolates were genetically distinct, and most closely related to the Australian marsupial trypanosomes H25 from a kangaroo, and BRA2 from a bush rat. This is the first study to genetically characterise trypanosome isolates from possums. The analysis of the woylie-derived isolates demonstrated that this marsupial host can harbour multiple genotypes within the same geographical location and furthermore multiple genotypes within the same host, indicative of mixed infections. All the woylie-derived genotypes grouped with trypanosomes found in Australian marsupials, suggesting that they are more likely to belong to an endemic or Australasian trypanosome species. This is the first study to genetically characterise trypanosome isolates from possums (Trichosurus vulpecula). Although the clinical significance of these infections is currently unknown, the identification of these novel sequences may support future investigations on transmission, threats to endangered wildlife, and evolutionary history of the genus Trypanosoma
Approximating the inspiral of test bodies into Kerr black holes
We present a new approximate method for constructing gravitational radiation
driven inspirals of test-bodies orbiting Kerr black holes. Such orbits can be
fully described by a semi-latus rectum , an eccentricity , and an
inclination angle ; or, by an energy , an angular momentum component
, and a third constant . Our scheme uses expressions that are exact
(within an adiabatic approximation) for the rates of change (,
, ) as linear combinations of the fluxes (,
, ), but uses quadrupole-order formulae for these fluxes.
This scheme thus encodes the exact orbital dynamics, augmenting it with
approximate radiation reaction. Comparing inspiral trajectories, we find that
this approximation agrees well with numerical results for the special cases of
eccentric equatorial and circular inclined orbits, far more accurate than
corresponding weak-field formulae for (, , ). We
use this technique to study the inspiral of a test-body in inclined, eccentric
Kerr orbits. Our results should be useful tools for constructing approximate
waveforms that can be used to study data analysis problems for the future LISA
gravitational-wave observatory, in lieu of waveforms from more rigorous
techniques that are currently under development.Comment: 15 pages, 5 figures, submitted to PR
Piroplasms of New Zealand seabirds
Blood and ectoparasitic ticks were collected from migratory seabirds in New Zealand, including Australasian gannets (n=13) from two sites and red-billed gulls (n=9) and white-fronted terns (n=2) from a third location. Blood smears were screened for parasite presence by microscopy, while DNA from blood samples was subjected to PCR for the presence of tick-transmitted protozoan haemoparasites belonging to the order Piroplasmida. Parasites were identified by comparing small subunit ribosomal RNA (18S rDNA) gene sequences to related sequences on GenBank. Analyses indicated that nine birds were infected with unknown variants of a Babesia poelea-like parasite (recorded as genotypes I and II), while four harboured a piroplasm that was genetically similar to Babesia kiwiensis. There was no parasite stratification by bird species; both the gannets and gulls were positive for all three parasites, while the terns were positive for the B. kiwiensis-like and the B. poelea-like (genotype I) parasites. The B. kiwiensis-like parasite found in the birds was also found in two species of ticks: Carios capensis and Ixodes eudyptidis. This represents the first report of Babesia-positive ticks parasitising seabirds in New Zealand. The lack of host specificity and evidence of wide ranging distributions of the three piroplasm genotypes suggests there is a high degree of haemoparasite transmission occurring naturally between New Zealand seabird populations and species
Young people, school engagement and perceptions of support: a mixed methods analysis
As levels of young people not in education, employment or training (NEET) remain high in the UK, there is growing concern about processes of school disengagement. Drawing on quantitative and qualitative data, we explore some factors that lead young people to disengage from – and potentially re-engage with – schooling. The research employed a sequential design with a quantitative survey of students, followed by two rounds of interviews with a sub-sample of young people. Statistical analysis of our survey confirmed that, for our respondents, school engagement is mediated through perceptions of support. Through longitudinal qualitative data, we consider which sources of support appear to be most important for participants, how changes in perceptions of support affect levels of engagement and how these may change over time. We aim to contribute to the literature by showing that increasing perceptions of support can positively influence school engagement. Drawing on theories of social capital, we illustrate how complex and dynamic interplays between diffuse actors can provide access to differentiated resources, including economic, social and cultural capital, with varied outcomes for school engagement. We also show how fluid and dynamic processes of engagement and the interplay with support can provide opportunities for promoting positive educational outcomes
Evolution of circular, non-equatorial orbits of Kerr black holes due to gravitational-wave emission: II. Inspiral trajectories and gravitational waveforms
The inspiral of a ``small'' () compact body into a
``large'' () black hole is a key source of
gravitational radiation for the space-based gravitational-wave observatory
LISA. The waves from such inspirals will probe the extreme strong-field nature
of the Kerr metric. In this paper, I investigate the properties of a restricted
family of such inspirals (the inspiral of circular, inclined orbits) with an
eye toward understanding observable properties of the gravitational waves that
they generate. Using results previously presented to calculate the effects of
radiation reaction, I assemble the inspiral trajectories (assuming that
radiation reacts adiabatically, so that over short timescales the trajectory is
approximately geodesic) and calculate the wave generated as the compact body
spirals in. I do this analysis for several black hole spins, sampling a range
that should be indicative of what spins we will encounter in nature. The spin
has a very strong impact on the waveform. In particular, when the hole rotates
very rapidly, tidal coupling between the inspiraling body and the event horizon
has a very strong influence on the inspiral time scale, which in turn has a big
impact on the gravitational wave phasing. The gravitational waves themselves
are very usefully described as ``multi-voice chirps'': the wave is a sum of
``voices'', each corresponding to a different harmonic of the fundamental
orbital frequencies. Each voice has a rather simple phase evolution. Searching
for extreme mass ratio inspirals voice-by-voice may be more effective than
searching for the summed waveform all at once.Comment: 15 pages, 11 figures, accepted for publication in PRD. This version
incorporates referee's comments, and is much less verbos
Information and education provision in bronchiectasis: co-development and evaluation of a novel patient-driven resource in a digital era
‘Take home message’
Improvements in information for those living with bronchiectasis should use patient driven co-development processes
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