87 research outputs found
Providing True Opportunity for Opportunity Youth: Promising Practices and Principles for Helping Youth Facing Barriers to Employment
Many "opportunity youth" -- youth who are not working or in school -- would benefit substantially from gaining work experience but need help overcoming barriers to employment and accessing the labor market.Those opportunity youth facing the most significant challenges, such as extreme poverty, homelessness, and justice system involvement, often need even more intensive assistance in entering and keeping employment, and are at risk of being left behind even by employment programs that are specifically designed to serve opportunity youth.This paper builds on the research literature with extensive interviews with employment program providers who have had success in helping the most vulnerable opportunity youth succeed in the workforce. Six principles for effectively serving these youth are identified
Robust Weak-lensing Mass Calibration of Planck Galaxy Clusters
In light of the tension in cosmological constraints reported by the Planck
team between their SZ-selected cluster counts and Cosmic Microwave Background
(CMB) temperature anisotropies, we compare the Planck cluster mass estimates
with robust, weak-lensing mass measurements from the Weighing the Giants (WtG)
project. For the 22 clusters in common between the Planck cosmology sample and
WtG, we find an overall mass ratio of \left =
0.688 \pm 0.072. Extending the sample to clusters not used in the Planck
cosmology analysis yields a consistent value of from 38 clusters in common. Identifying the
weak-lensing masses as proxies for the true cluster mass (on average), these
ratios are lower than the default mass bias of 0.8 assumed in
the Planck cluster analysis. Adopting the WtG weak-lensing-based mass
calibration would substantially reduce the tension found between the Planck
cluster count cosmology results and those from CMB temperature anisotropies,
thereby dispensing of the need for "new physics" such as uncomfortably large
neutrino masses (in the context of the measured Planck temperature anisotropies
and other data). We also find modest evidence (at 95 per cent confidence) for a
mass dependence of the calibration ratio and discuss its potential origin in
light of systematic uncertainties in the temperature calibration of the X-ray
measurements used to calibrate the Planck cluster masses. Our results exemplify
the critical role that robust absolute mass calibration plays in cluster
cosmology, and the invaluable role of accurate weak-lensing mass measurements
in this regard.Comment: 5 pages, 2 figure
Household networks and emergent territory: a GIS study of Chumash households, villages and rock-art in South-Central California
Elite households of the Californian Chumash have been studied in order to understand the development of Late Holocene hunter-gatherer alliance networks. Equally, models of what has been termed ‘tribelet territories’ have been used to describe land ownership within larger Californian concepts. Surprisingly little research has explicitly addressed issues of how such territories may have developed. In this article, we turn to DeLanda’s philosophy of social complexity to consider how Chumash households may have underpinned the development of tribelet territories and the political implications for their articulation with wider alliances. Importantly, utilizing Geographic Information Systems (GIS), we analyse potential mobility patterns in relation to households, villages and rock-art locales in a case from the Emigdiano Chumash. The results suggest that the painting of rock art was imbricated within processes of territorialization, and that the local placement of art reflects which villages were home to particularly high-status households
Weighing the Giants - I. Weak-lensing masses for 51 massive galaxy clusters: project overview, data analysis methods and cluster images
This is the first in a series of papers in which we measure accurate
weak-lensing masses for 51 of the most X-ray luminous galaxy clusters known at
redshifts 0.15<z<0.7, in order to calibrate X-ray and other mass proxies for
cosmological cluster experiments. The primary aim is to improve the absolute
mass calibration of cluster observables, currently the dominant systematic
uncertainty for cluster count experiments. Key elements of this work are the
rigorous quantification of systematic uncertainties, high-quality data
reduction and photometric calibration, and the "blind" nature of the analysis
to avoid confirmation bias. Our target clusters are drawn from RASS X-ray
catalogs, and provide a versatile calibration sample for many aspects of
cluster cosmology. We have acquired wide-field, high-quality imaging using the
Subaru and CFHT telescopes for all 51 clusters, in at least three bands per
cluster. For a subset of 27 clusters, we have data in at least five bands,
allowing accurate photo-z estimates of lensed galaxies. In this paper, we
describe the cluster sample and observations, and detail the processing of the
SuprimeCam data to yield high-quality images suitable for robust weak-lensing
shape measurements and precision photometry. For each cluster, we present
wide-field color optical images and maps of the weak-lensing mass distribution,
the optical light distribution, and the X-ray emission, providing insights into
the large-scale structure in which the clusters are embedded. We measure the
offsets between X-ray centroids and Brightest Cluster Galaxies in the clusters,
finding these to be small in general, with a median of 20kpc. For offsets
<100kpc, weak-lensing mass measurements centered on the BCGs agree well with
values determined relative to the X-ray centroids; miscentering is therefore
not a significant source of systematic uncertainty for our mass measurements.
[abridged]Comment: 26 pages, 19 figures (Appendix C not included). Accepted after minor
revisio
Significance of Elevated Blood Metal Ion Levels in Patients with Metal-on-Metal Prostheses: An Evaluation of Oxidative Stress Markers
It is widely known that cobalt and chromium ions can enhance the production of reactive oxygen species, known to be damaging to cells by disturbing their redox status and then generating oxidative stress. The aim of the present study was to determine if increased metal ion levels induce a state of oxidative stress in patients with metal-on-metal (MM) hip arthroplasty. Results indicated that there was no significant difference in the concentration of oxidative stress markers (total antioxidants, peroxides, and nitrated proteins) in the patients with MM bearings compared to patients without prostheses. The activity antioxidant enzymes was stable (catalase and glutathione peroxidase) or slightly decreased (superoxide dismutase and heme oxygenase-1) over time. This work is the first to determine the biological effects of metal ions released from MM hip implants with regards to mid-term systemic oxidative stress and showed that the increased levels of Co and Cr ions are not associated with significant oxidative stress damage in the plasma of patients with these implants
Weighing the giants – IV. Cosmology and neutrino mass
We employ robust weak gravitational lensing measurements to improve
cosmological constraints from measurements of the galaxy cluster mass function
and its evolution, using X-ray selected clusters detected in the ROSAT All-Sky
Survey. Our lensing analysis constrains the absolute mass scale of such
clusters at the 8 per cent level, including both statistical and systematic
uncertainties. Combining it with the survey data and X-ray follow-up
observations, we find a tight constraint on a combination of the mean matter
density and late-time normalization of the matter power spectrum,
, with marginalized, one-dimensional
constraints of and . For these two
parameters, this represents a factor of two improvement in precision with
respect to previous work, primarily due to the reduced systematic uncertainty
in the absolute mass calibration provided by the lensing analysis. Our new
results are in good agreement with constraints from cosmic microwave background
(CMB) data, both WMAP and Planck (plus WMAP polarization), under the assumption
of a flat CDM cosmology with minimal neutrino mass. Consequently, we
find no evidence for non-minimal neutrino mass from the combination of cluster
data with CMB, supernova and baryon acoustic oscillation measurements,
regardless of which all-sky CMB data set is used (and independent of the recent
claimed detection of B-modes on degree scales). We also present improved
constraints on models of dark energy (both constant and evolving),
modifications of gravity, and primordial non-Gaussianity. Assuming flatness,
the constraints for a constant dark energy equation of state from the cluster
data alone are at the 15 per cent level, improving to per cent when
the cluster data are combined with other leading probes.Comment: 24 pages, 10 figures, 5 tables. v3: typo in table A1 correcte
Mechanisms of Hearing Loss after Blast Injury to the Ear
Given the frequent use of improvised explosive devices (IEDs) around the world, the study of traumatic blast injuries is of
increasing interest. The ear is the most common organ affected by blast injury because it is the bodyメs most sensitive
pressure transducer. We fabricated a blast chamber to re-create blast profiles similar to that of IEDs and used it to develop a
reproducible mouse model to study blast-induced hearing loss. The tympanic membrane was perforated in all mice after
blast exposure and found to heal spontaneously. Micro-computed tomography demonstrated no evidence for middle ear or
otic capsule injuries; however, the healed tympanic membrane was thickened. Auditory brainstem response and distortion
product otoacoustic emission threshold shifts were found to be correlated with blast intensity. As well, these threshold
shifts were larger than those found in control mice that underwent surgical perforation of their tympanic membranes,
indicating cochlear trauma. Histological studies one week and three months after the blast demonstrated no disruption or
damage to the intra-cochlear membranes. However, there was loss of outer hair cells (OHCs) within the basal turn of the
cochlea and decreased spiral ganglion neurons (SGNs) and afferent nerve synapses. Using our mouse model that
recapitulates human IED exposure, our results identify that the mechanisms underlying blast-induced hearing loss does not
include gross membranous rupture as is commonly believed. Instead, there is both OHC and SGN loss that produce auditory
dysfunction
Improving communication and recall of information in paediatric diabetes consultations: a qualitative study of parents' experiences and views
Background
Parents of non-adolescent children with type 1 diabetes are responsible for most of their child’s diabetes management tasks. Consultations are used to provide diabetes education, review clinical progress and promote diabetes management tasks. This study explored parents’ experiences of, and views about, their child’s diabetes consultations. The objective was to identify ways in which consultations could be improved to aid communication, understanding and knowledge retention.
Methods
In-depth interviews with 54 parents of children (aged ≤12 years) with type 1 diabetes. Data were analysed using an inductive thematic approach.
Results
Parents’ accounts revealed structural and contextual factors which could hinder effective communication and knowledge acquisition during consultations. Most reported feeling anxious going into consultations and worrying about being reprimanded by health professionals if their child’s glycaemic control had not improved. As a consequence, many parents highlighted problems concentrating and assimilating information during consultations. In extreme cases, worries about being reprimanded led parents to omit or fabricate information when discussing their child’s treatment or even to their cancelling appointments. Many parents described wanting opportunities to speak to health professionals alone because young children could be distracting and/or they did not want to raise distressing issues in front of their child. Parents described the benefits of receiving clinical advice from health professionals familiar with their family circumstances and disliking attending busy clinics and seeing different health professionals on each occasion. Parents also highlighted the benefits of receiving treatment recommendations in a written form after the consultation.
Discussion and conclusions
This study has highlighted unrecognised and undocumented aspects of the consultation which may result in parents leaving uncertain about the main issues discussed and with questions unanswered and support needs unaddressed. Structural and contextual changes to consultations are recommended to improve concentration, knowledge acquisition and retention. These include: sending letters/written summaries after consultations highlighting key decisions, providing opportunities for parents to consult health professionals without their child being present, encouraging parents to ask more questions during consultations, having procedures in place to promote continuity of care and providing parents with consistent and non-contradictory advice
Dispersion as an Important Step in the Candida albicans Biofilm Developmental Cycle
Biofilms are dynamic microbial communities in which transitions between planktonic and sessile modes of growth occur interchangeably in response to different environmental cues. In the last decade, early events associated with C. albicans biofilm formation have received considerable attention. However, very little is known about C. albicans biofilm dispersion or the mechanisms and signals that trigger it. This is important because it is precisely C. albicans cells dispersed from biofilms that are the main culprits associated with candidemia and establishment of disseminated invasive disease, two of the gravest forms of candidiasis. Using a simple flow biofilm model recently developed by our group, we have performed initial investigations into the phenomenon of C. albicans biofilm dispersion, as well as the phenotypic characteristics associated with dispersed cells. Our results indicate that C. albicans biofilm dispersion is dependent on growing conditions, including carbon source and pH of the media used for biofilm development. C. albicans dispersed cells are mostly in the yeast form and display distinct phenotypic properties compared to their planktonic counterparts, including enhanced adherence, filamentation, biofilm formation and, perhaps most importantly, increased pathogenicity in a murine model of hematogenously disseminated candidiasis, thus indicating that dispersed cells are armed with a complete arsenal of “virulence factors” important for seeding and establishing new foci of infection. In addition, utilizing genetically engineered strains of C. albicans (tetO-UME6 and tetO-PES1) we demonstrate that C. albicans biofilm dispersion can be regulated by manipulating levels of expression of these key genes, further supporting the evidence for a strong link between biofilms and morphogenetic conversions at different stages of the C. albicans biofilm developmental cycle. Overall, our results offer novel and important insight into the phenomenon of C. albicans biofilm dispersion, a key part of the biofilm developmental cycle, and provide the basis for its more detailed analysis
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