1,287 research outputs found
Opportunities and barriers in paediatric pulse oximetry for pneumonia in low-resource clinical settings: a qualitative evaluation from Malawi and Bangladesh
OBJECTIVE: To gain an understanding of what challenges pulse oximetry for paediatric pneumonia management poses, how it has changed service provision and what would improve this device for use across paediatric clinical settings in low-income countries. DESIGN: Focus group discussions (FGDs), with purposive sampling and thematic analysis using a framework approach. SETTING: Community, front-line outpatient, and hospital outpatient and inpatient settings in Malawi and Bangladesh, which provide paediatric pneumonia care. PARTICIPANTS: Healthcare providers (HCPs) from Malawi and Bangladesh who had received training in pulse oximetry and had been using oximeters in routine paediatric care, including community healthcare workers, non-physician clinicians or medical assistants, and hospital-based nurses and doctors. RESULTS: We conducted six FGDs, with 23 participants from Bangladesh and 26 from Malawi. We identified five emergent themes: trust, value, user-related experience, sustainability and design. HCPs discussed the confidence gained through the use of oximeters, resulting in improved trust from caregivers and valuing the device, although there were conflicts between the weight given to clinical judgement versus oximeter results. HCPs reported the ease of using oximeters, but identified movement and physically smaller children as measurement challenges. Challenges in sustainability related to battery durability and replacement parts, however many HCPs had used the same device longer than 4 years, demonstrating robustness within these settings. Desirable features included back-up power banks and integrated respiratory rate and thermometer capability. CONCLUSIONS: Pulse oximetry was generally deemed valuable by HCPs for use as a spot-check device in a range of paediatric low-income clinical settings. Areas highlighted as challenges by HCPs, and therefore opportunities for redesign, included battery charging and durability, probe fit and sensitivity in paediatric populations. TRIAL REGISTRATION NUMBER: NCT02941237
Principal Component Analysis Using Structural Similarity Index for Images
Despite the advances of deep learning in specific tasks using images, the
principled assessment of image fidelity and similarity is still a critical
ability to develop. As it has been shown that Mean Squared Error (MSE) is
insufficient for this task, other measures have been developed with one of the
most effective being Structural Similarity Index (SSIM). Such measures can be
used for subspace learning but existing methods in machine learning, such as
Principal Component Analysis (PCA), are based on Euclidean distance or MSE and
thus cannot properly capture the structural features of images. In this paper,
we define an image structure subspace which discriminates different types of
image distortions. We propose Image Structural Component Analysis (ISCA) and
also kernel ISCA by using SSIM, rather than Euclidean distance, in the
formulation of PCA. This paper provides a bridge between image quality
assessment and manifold learning opening a broad new area for future research.Comment: Paper for the methods named "Image Structural Component Analysis
(ISCA)" and "Kernel Image Structural Component Analysis (Kernel ISCA)
Are genetic risk factors for psychosis also associated with dimension-specific psychotic experiences in adolescence?
Psychosis has been hypothesised to be a continuously distributed quantitative phenotype and disorders such as schizophrenia and bipolar disorder represent its extreme manifestations. Evidence suggests that common genetic variants play an important role in liability to both schizophrenia and bipolar disorder. Here we tested the hypothesis that these common variants would also influence psychotic experiences measured dimensionally in adolescents in the general population. Our aim was to test whether schizophrenia and bipolar disorder polygenic risk scores (PRS), as well as specific single nucleotide polymorphisms (SNPs) previously identified as risk variants for schizophrenia, were associated with adolescent dimension-specific psychotic experiences. Self-reported Paranoia, Hallucinations, Cognitive Disorganisation, Grandiosity, Anhedonia, and Parent-rated Negative Symptoms, as measured by the Specific Psychotic Experiences Questionnaire (SPEQ), were assessed in a community sample of 2,152 16-year-olds. Polygenic risk scores were calculated using estimates of the log of odds ratios from the Psychiatric Genomics Consortium GWAS stage-1 mega-analysis of schizophrenia and bipolar disorder. The polygenic risk analyses yielded no significant associations between schizophrenia and bipolar disorder PRS and the SPEQ measures. The analyses on the 28 individual SNPs previously associated with schizophrenia found that two SNPs in TCF4 returned a significant association with the SPEQ Paranoia dimension, rs17512836 (p-value=2.57x10-4) and rs9960767 (p-value=6.23x10-4). Replication in an independent sample of 16-year-olds (N=3,427) assessed using the Psychotic-Like Symptoms Questionnaire (PLIKS-Q), a composite measure of multiple positive psychotic experiences, failed to yield significant results. Future research with PRS derived from larger samples, as well as larger adolescent validation samples, would improve the predictive power to test these hypotheses further. The challenges of relating adult clinical diagnostic constructs such as schizophrenia to adolescent psychotic experiences at a genetic level are discussed
Obtaining antibiotics online from within the UK: a cross-sectional study
BACKGROUND: Improved antibiotic stewardship (AS) and reduced prescribing in primary care, with a parallel increase in personal internet use, could lead citizens to obtain antibiotics from alternative sources online. OBJECTIVES: A cross-sectional analysis was performed to: (i) determine the quality and legality of online pharmacies selling antibiotics to the UK public; (ii) describe processes for obtaining antibiotics online from within the UK; and (iii) identify resulting AS and patient safety issues. METHODS: Searches were conducted for 'buy antibiotics online' using Google and Yahoo. For each search engine, data from the first 10 web sites with unique URL addresses were reviewed. Analysis was conducted on evidence of appropriate pharmacy registration, prescription requirement, whether antibiotic choice was 'prescriber-driven' or 'consumer-driven', and whether specific information was required (allergies, comorbidities, pregnancy) or given (adverse effects) prior to purchase. RESULTS: Twenty unique URL addresses were analysed in detail. Online pharmacies evidencing their location in the UK ( n = 5; 25%) required a prescription before antibiotic purchase, and were appropriately registered. Online pharmacies unclear about the location they were operating from ( n = 10; 50%) had variable prescription requirements, and no evidence of appropriate registration. Nine (45%) online pharmacies did not require a prescription prior to purchase. For 16 (80%) online pharmacies, decisions were initially consumer-driven for antibiotic choice, dose and quantity. CONCLUSIONS: Wide variation exists among online pharmacies in relation to antibiotic practices, highlighting considerable patient safety and AS issues. Improved education, legislation, regulation and new best practice stewardship guidelines are urgently needed for online antibiotic suppliers
Electronic structure, linear, nonlinear optical susceptibilities and birefringence of CuInX2 (X = S, Se, Te) chalcopyrite-structure compounds
The electronic structure, linear and nonlinear optical properties have been
calculated for CuInX2 (X=S, Se, Te) chalcopyrite-structure single crystals
using the state-of-the-art full potential linear augmented plane wave (FP-LAPW)
method. We present results for band structure, density of states, and imaginary
part of the frequency-dependent linear and nonlinear optical susceptibilities.
We find that these crystals are semiconductors with direct band gaps. We have
calculated the birefringence of these crystals. The birefringence is negative
for CuInS2 and CuInSe2 while it is positive for CuInTe2 in agreement with the
experimental data. Calculations are reported for the frequency-dependent
complex second-order non-linear optical susceptibilities . The intra-band and
inter-band contributions to the second harmonic generation increase when we
replace S by Se and decrease when we replace Se by Te. We find that smaller
energy band gap compounds have larger values of in agreement with the
experimental data and previous theoretical calculations.Comment: 17 pages, 6 figure
Background risk of breast cancer and the association between physical activity and mammographic density
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International License. The images or other third party material in this
article are included in the article’s Creative Commons license, unless indicated
otherwise in the credit line; if the material is not included under the Creative Commons
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material. To view a copy of this license, visit http://creativecommons.org/licenses/
by/4.0
Electromagnetically Induced Transparency and Slow Light with Optomechanics
Controlling the interaction between localized optical and mechanical
excitations has recently become possible following advances in micro- and
nano-fabrication techniques. To date, most experimental studies of
optomechanics have focused on measurement and control of the mechanical
subsystem through its interaction with optics, and have led to the experimental
demonstration of dynamical back-action cooling and optical rigidity of the
mechanical system. Conversely, the optical response of these systems is also
modified in the presence of mechanical interactions, leading to strong
nonlinear effects such as Electromagnetically Induced Transparency (EIT) and
parametric normal-mode splitting. In atomic systems, seminal experiments and
proposals to slow and stop the propagation of light, and their applicability to
modern optical networks, and future quantum networks, have thrust EIT to the
forefront of experimental study during the last two decades. In a similar
fashion, here we use the optomechanical nonlinearity to control the velocity of
light via engineered photon-phonon interactions. Our results demonstrate EIT
and tunable optical delays in a nanoscale optomechanical crystal device,
fabricated by simply etching holes into a thin film of silicon (Si). At low
temperature (8.7 K), we show an optically-tunable delay of 50 ns with
near-unity optical transparency, and superluminal light with a 1.4 microseconds
signal advance. These results, while indicating significant progress towards an
integrated quantum optomechanical memory, are also relevant to classical signal
processing applications. Measurements at room temperature and in the analogous
regime of Electromagnetically Induced Absorption (EIA) show the utility of
these chip-scale optomechanical systems for optical buffering, amplification,
and filtering of microwave-over-optical signals.Comment: 15 pages, 9 figure
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Anticipatory governance for social-ecological resilience
Anticipation is increasingly central to urgent contemporary debates, from climate change to the global economic crisis. Anticipatory practices are coming to the forefront of political, organizational, and citizens’ society. Research into anticipation, however, has not kept pace with public demand for insights into anticipatory practices, their risks and uses. Where research exists, it is deeply fragmented. This paper seeks to identify how anticipation is defined and understood in the literature and to explore the role of anticipatory practice to address individual, social, and global challenges. We use a resilience lens to examine these questions. We illustrate how varying forms of anticipatory governance are enhanced by multi-scale regional networks and technologies and by the agency of individuals, drawing from an empirical case study on regional water governance of Malaren, Sweden. Finally, we discuss how an anticipatory approach can inform adaptive institutions, decision making, strategy formation, and societal resilience
Weighted Fisher Discriminant Analysis in the Input and Feature Spaces
Fisher Discriminant Analysis (FDA) is a subspace learning method which
minimizes and maximizes the intra- and inter-class scatters of data,
respectively. Although, in FDA, all the pairs of classes are treated the same
way, some classes are closer than the others. Weighted FDA assigns weights to
the pairs of classes to address this shortcoming of FDA. In this paper, we
propose a cosine-weighted FDA as well as an automatically weighted FDA in which
weights are found automatically. We also propose a weighted FDA in the feature
space to establish a weighted kernel FDA for both existing and newly proposed
weights. Our experiments on the ORL face recognition dataset show the
effectiveness of the proposed weighting schemes.Comment: Accepted (to appear) in International Conference on Image Analysis
and Recognition (ICIAR) 2020, Springe
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