2,439 research outputs found
Nanoscale quantum dot infrared sensors with photonic crystal cavity
We report high performance infrared sensors that are based on intersubband transitions in nanoscale self-assembled quantum dots combined with a microcavity resonator made with a high-index-contrast two-dimensional photonic crystal. The addition of the photonic crystal cavity increases the photocurrent, conversion efficiency, and the signal to noise ratio (represented by the specific detectivity D*) by more than an order of magnitude. The conversion efficiency of the detector at Vb=–2.6 V increased from 7.5% for the control sample to 95% in the PhC detector. In principle, these photonic crystal resonators are technology agnostic and can be directly integrated into the manufacturing of present day infrared sensors using existing lithographic tools in the fabrication facility
Hepatitis C prevalences in the psychiatric setting: Cost-effectiveness of scaling-up screening and direct-acting antiviral therapy.
Patients hospitalised because of mental illness often have risk factors for contracting HCV. Scaling-up HCV screening for all psychiatric inpatients as a case-detection strategy for viral elimination is underexplored. This study aimed to evaluate the cost-effectiveness of scaling-up HCV screening and treatment for psychiatry hospital admissions in Switzerland vs. the current standard-of-care risk-based approach, where only those with a history of substance misuse disorder are offered testing.
HCV prevalence by history of substance misuse disorder was analysed in medical records from inpatient admissions to a Swiss psychiatry department. Cost-effectiveness was analysed from a healthcare provider perspective through a decision-tree screening model, using these HCV prevalence data. Model and parameter uncertainty were assessed using deterministic and probabilistic sensitivity analyses.
Prevalence of HCV in psychiatry inpatients with a history of substance misuse disorder (n = 1,013) was 25.7%, compared with 3.5% among the remaining inpatients (n = 3,535). Scaling up HCV screening and treatment for all psychiatry admissions was cost-effective vs. the risk-based approach, with an incremental cost-effectiveness ratio of US435,156,348, with 917 additional patients per year detected and treated at a cost of US2,122 under risk-based screening).
Scaling up HCV screening and treatment at diagnosis with all-oral, interferon-free regimens as a generalised approach for psychiatric admissions was cost-effective and could support reaching World Health Organization targets for HCV elimination by 2030.
Patients hospitalised because of mental illness often have risk factors for HCV. We found that testing all psychiatry patients in hospital for HCV was cost-effective compared with testing only patients who have a history of substance misuse. Scaling up HCV testing and treatment could help to wipe out HCV
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Case study of spatial and temporal variability of snow cover, grain size, albedo and radiative forcing in the Sierra Nevada and Rocky Mountain snowpack derived from imaging spectroscopy
Quantifying the spatial distribution and temporal change in mountain snow
cover, microphysical and optical properties is important to improve our
understanding of the local energy balance and the related snowmelt and
hydrological processes. In this paper, we analyze changes of snow cover,
optical-equivalent snow grain size (radius), snow albedo and radiative
forcing by light-absorbing impurities in snow and ice (LAISI) with respect to
terrain elevation and aspect at multiple dates during the snowmelt period.
These snow properties are derived from the NASA/JPL Airborne Visible/Infrared
Imaging Spectrometer (AVIRIS) data from 2009 in California's Sierra Nevada
and from 2011 in Colorado's Rocky Mountains, USA.
Our results show a linearly decreasing snow cover during the ablation period
in May and June in the Rocky Mountains and a snowfall-driven change in snow
cover in the Sierra Nevada between February and May. At the same time, the
snow grain size is increasing primarily at higher elevations and north-facing
slopes from 200 microns to 800 microns on average. We find that intense
snowmelt renders the mean grain size almost invariant with respect to
elevation and aspect. Our results confirm the inverse relationship between
snow albedo and grain size, as well as between snow albedo and radiative
forcing by LAISI. At both study sites, the mean snow albedo value decreases
from approximately 0.7 to 0.5 during the ablation period. The mean snow grain
size increased from approximately 150 to 650 microns. The mean radiative
forcing increases from 20 W m−2 up to 200 W m−2 during the
ablation period. The variability of snow albedo and grain size decreases in
general with the progression of the ablation period. The spatial variability
of the snow albedo and grain size decreases through the melt season while the
spatial variability of radiative forcing remains constant.</p
Reconceptualizing CSR in the media industry as relational accountability
In this paper, we reconceptualize CSR in the media industries by combining empirical data with theoretical perspectives emerging from the communication studies and business ethics literature. We develop a new conception of what corporate responsibility in media organizations may mean in real terms by bringing Bardoel and d’Haenens’ (European Journal of Communication 19 165–194 2004) discussion of the different dimensions of media accountability into conversation with the empirical results from three international focus group studies, conducted in France, the USA and South Africa. To enable a critical perspective on our findings, we perform a philosophical analysis of its implications for professional, public, market, and political accountability in the media, drawing on the insights of Paul Virilio. We come to the conclusion that though some serious challenges to media accountability exist, the battle for responsible media industries is not lost. In fact, the speed characterizing the contemporary media environment may hold some promise for fostering the kind of relational accountability that could underpin a new understanding of CSR in the media
Visual portrayals of fun in the sun in European news outlets misrepresent heatwave risks
This is the author accepted manuscript. Available on open access from Wiley via the DOI in this recordData availability statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.The ways in which news media communicate about heatwaves can influence how society conceptualises and addresses heatwave risks. We examined visual news coverage of the 2019 heatwaves in France, Germany, the Netherlands and UK, using content and visual critical discourse analyses. Many visuals were positively valenced (in contrast to article texts), framing heatwaves as ‘fun in the sun’. The most prevalent type of images in all countries were photographs of people having fun in or by water. When images did depict the danger of heat extremes, people were largely absent. We conclude that this visual framing of heatwaves is problematic: first, by displacing concerns of vulnerability, it marginalises the experiences of those vulnerable to heatwaves; and second, it excludes opportunities for imagining a more resilient future. We conclude with suggestions to diversify the visual discourse on climate change and heatwaves in the news media.Leverhulme TrustEconomic and Social Research Council (ESRC
The Color of Childhood: The Role of the Child/Human Binary in the Production of Anti-Black Racism
The binary between the figure of the child and the fully human being is invoked with regularity in analyses of race, yet its centrality to the conception of race has never been fully explored. For most commentators, the figure of the child operates as a metaphoric or rhetorical trope, a non-essential strategic tool in the perpetuation of White supremacy. As I show in the following, the child/human binary does not present a contingent or merely rhetorical construction but, rather, a central feature of racialization. Where Black peoples are situated as objects of violence it is often precisely because Blackness has been identified with childhood and childhood is historically identified as the archetypal site of naturalized violence and servitude. I proceed by offering a historical account of how Black peoples came to inherit the subordination and dehumanization of European childhood and how White youth were subsequently spared through their partial categorization as adults
Exploring the science–policy interface on climate change: The role of the IPCC in informing local decision-making in the UK
Building on the Intergovernmental Panel on Climate Change’s (IPCC) review of
how to make its Assessment Reports (ARs) more accessible in the future, the research
reported here assesses the extent to which the ARs are a useful tool through which scientific
advice informs local decision-making on climate change in the United Kingdom. Results from
interviews with local policy representatives and three workshops with UK academics, practitioners
and local decision makers are presented. Drawing on these data, we outline three
key recommendations made by participants on how the IPCC ARs can be better utilized as a
form of scientific advice to inform local decision-making on climate change. First, to provide
more succinct summaries of the reports paying close attention to the language, content,
clarity, context and length of these summaries; second, to better target and frame the reports
from a local perspective to maximize engagement with local stakeholders; and third, to work
with local decision makers to better understand how scientific advice on climate change is
being incorporated in local decision-making. By adopting these, the IPCC would facilitate local
decision-making on climate change and provide a systematic review of how its reports are
being used locally. We discuss implications of these recommendations and their relevance to
the wider debate within and outside the IPCC as to the most effective way the IPCC can more
effectively tailor its products to user needs without endangering the robustness of its scientific
findings. This article is published as part of a collection on scientific advice to government
Nonlinear localized waves in a periodic medium
We analyze the existence and stability of nonlinear localized waves in a
periodic medium described by the Kronig-Penney model with a nonlinear defect.
We demonstrate the existence of a novel type of stable nonlinear band-gap
localized states, and also reveal an important physical mechanism of the
oscillatory wave instabilities associated with the band-gap resonances.Comment: 4 pages, 5 figure
An Inverse-Problem Approach to Designing Photonic Crystals for Cavity QED Experiments
Photonic band gap (PBG) materials are attractive for cavity QED experiments
because they provide extremely small mode volumes and are monolithic,
integratable structures. As such, PBG cavities are a promising alternative to
Fabry-Perot resonators. However, the cavity requirements imposed by QED
experiments, such as the need for high Q (low cavity damping) and small mode
volumes, present significant design challenges for photonic band gap materials.
Here, we pose the PBG design problem as a mathematical inversion and provide an
analytical solution for a two-dimensional crystal. We then address a planar (2D
crystal with finite thickness) structure using numerical techniques.Comment: 12 pages, 8 figures, preprint available from
http://minty.caltech.edu/MabuchiLa
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