4,680 research outputs found

    Joint Blind Motion Deblurring and Depth Estimation of Light Field

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    Removing camera motion blur from a single light field is a challenging task since it is highly ill-posed inverse problem. The problem becomes even worse when blur kernel varies spatially due to scene depth variation and high-order camera motion. In this paper, we propose a novel algorithm to estimate all blur model variables jointly, including latent sub-aperture image, camera motion, and scene depth from the blurred 4D light field. Exploiting multi-view nature of a light field relieves the inverse property of the optimization by utilizing strong depth cues and multi-view blur observation. The proposed joint estimation achieves high quality light field deblurring and depth estimation simultaneously under arbitrary 6-DOF camera motion and unconstrained scene depth. Intensive experiment on real and synthetic blurred light field confirms that the proposed algorithm outperforms the state-of-the-art light field deblurring and depth estimation methods

    “Disadvantaged patient populations”: A theory-informed education needs assessment in an urban teaching hospital

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    Recent calls in medical education and health care emphasize equitable care for disadvantaged patient populations (DPP), with education  highlighted as a key mechanism to move toward this goal. However, in order to develop effective education strategies we must first better understand the DPP concept. We conducted a theory-informed needs assessment to explore the concept of DPP as understood in our hospital.  Using an interpretive qualitative approach informed by principles of critical discourse analysis we conducted focus groups with trainees and staff across professions and groups, as identified in the hospital’s strategic plan, representing “patients experiencing disadvantage.” We identified three main perceptions about DPP:  1) disadvantaged patients require care above and beyond what is normal; 2) the system is to blame for failures in serving disadvantaged patients; and 3) labelling patients is problematic and stigmatizing. In response, patients wanted to be first seen as valuable human beings rather than as a burden or category. Patients appreciated that the DPP concept opened up better access to care, but also felt ‘othered’ by the concept. As a result, patients felt they were not accessing the same level of care in terms of compassion and respect.  Our findings suggest potential for three, theory-informed educational approaches to help improve care for patients experiencing disadvantage: 1) sharing authentic and varied stories; 2) fostering dialogue; and 3) aligning assessment approaches with educational approaches. Additionally, we suggest a need to define access beyond the ability to receive services; according to our participants, access must also engender a sense of common humanity and respect.&nbsp

    4-(4-Pyrid­yl)pyridinium 3-amino-5-carb­oxy-2,4,6-triiodo­benzoate–5-amino-2,4,6-triiodo­isophthalic acid (1/1)

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    In the title ammonium carboxyl­ate–carb­oxy­lic acid co-cystal, C10H9N2 +·C8H3I3NO4 −.C8H4I3NO4, the carboxyl­ate anion and carb­oxy­lic acid mol­ecule are linked by O—H⋯O and N—H⋯O hydrogen bonds to form a chain running along the c axis of the monoclinic unit cell. The chains are linked by pyridinum and pyridine N—H⋯O hydrogen bonds, generating a layer motif. O—H⋯N and O—H⋯O hydrogen bonds are also observed

    5-Amino-2,4,6-triiodo­isophthalic acid–4,4′-bipyridine N,N′-dioxide–water (1/1/1)

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    The aromatic rings of the N,N′-dioxide molecule in the title compound, C8H4NI3O4·C10H8N2O2·H2O, are twisted by 14.0 (2)°. The –CO2H substituents of the 5-amino-2,4,6-triiodo­isophthalic acid are twisted by 83.0 (2) and 86.5 (2)° out of the plane of the aromatic ring. In the crystal, the three components are linked by O—H⋯O hydrogen bonds into a three-dimensional network. An N—H⋯O inter­action also occurs. One of the amino H atom is not involved in hydrogen bonding

    A probabilistic approach for quantitative identification of multiple delaminations in laminated composite beams using guided waves

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    Available online 16 September 2016In this study a probabilistic approach is proposed to identify multiple delaminations in laminated composite beams using guided waves. The proposed method is a model-based approach, which provides a quantitative identification of the delaminations. This study puts forward a practical damage identification method, and hence, it can identify multiple delaminations using guided wave signal measured at a single measurement point on the laminated composite beams. The proposed method first determines the number of delaminations using Bayesian model class selection method. The Bayesian statistical framework is then employed to not only identify the delamination locations, lengths and through-thickness locations, but also quantify the associated uncertainties, which provides valuable information for engineers in making decision on necessary remedial work. In addition the proposed method employs the time-domain spectral finite element method and Bayesian updating with Subset simulation to further improve the computational efficiency. The proposed probabilistic approach is verified and demonstrated using data obtained from numerical simulations, which consider both measurement noise and modeling error, and experimental data. The results show that the proposed method can accurately determine the number of delaminations, and the identified delamination locations, lengths and through-thickness locations are closed to the true values.Shuai He, Ching-Tai N

    Indirect Detection of a Light Higgsino Motivated by Collider Data

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    Kane and Wells recently argued that collider data point to a Higgsino-like lightest supersymmetric partner which would explain the dark matter in our Galactic halo. They discuss direct detection of such dark-matter particles in laboratory detectors. Here, we argue that such a particle, if it is indeed the dark matter, might alternatively be accessible in experiments which search for energetic neutrinos from dark-matter annihilation in the Sun. We provide accurate analytic estimates for the rates which take into account all relevant physical effects. Currently, the predicted signal falls roughly one to three orders of magnitude below experimental bounds, depending on the mass and coupling of the particle; however, detectors such as MACRO, super-Kamiokande, and AMANDA will continue to take data and should be able to rule out or confirm an interesting portion of the possible mass range for such a dark-matter particle within the next five years.Comment: 10 pages, RevTe

    The Effect of Compositional Context on Synthetic Gene Networks

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    It is well known that synthetic gene expression is highly sensitive to how genetic elements (promoter structure, spacing regions between promoter and coding sequences, ribosome binding sites, etc.) are spatially configured. An important topic that has received far less attention is how the compositional context, or spatial arrangement, of entire genes within a synthetic gene network affects their individual expression levels. In this paper we show, both quantitatively and qualitatively, that compositional context significantly alters transcription levels in synthetic gene networks. We demonstrate that key characteristics of gene induction, such as ultra-sensitivity and dynamic range, strongly depend on compositional context. We postulate that supercoiling can be used to explain this interference and validate this hypothesis through modeling and a series of in vitro supercoiling relaxation experiments. This compositional interference enables a novel form of feedback in synthetic gene networks. We illustrate the use of this feedback by redesigning the toggle switch to incorporate compositional context. We show the context-optimized toggle switch has improved threshold detection and memory properties

    Guided wave-based identification of multiple cracks in beams using a Bayesian approach

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    Available online 26 July 2016A guided wave damage identification method using a model-based approach is proposed to identify multiple cracks in beam-like structures. The guided wave propagation is simulated using spectral finite element method and a crack element is proposed to take into account the mode conversion effect. The Bayesian model class selection algorithm is employed to determine the crack number and then the Bayesian statistical framework is used to identify the crack parameters and the associated uncertainties. In order to improve the efficiency and ensure the reliability of identification, the Transitional Markov Chain Monte Carlo (TMCMC) method is implemented in the Bayesian approach. A series of numerical case studies are carried out to assess the performance of the proposed method, in which the sensitivity of different guided wave modes and effect of different levels of measurement noise in identifying different numbers of cracks is studied in detail. The proposed method is also experimentally verified using guided wave data obtained from laser vibrometer. The results show that the proposed method is able to accurately identify the number, locations and sizes of the cracks, and also quantify the associated uncertainties. In addition the proposed method is robust under measurement noise and different situations of the cracks.Shuai He, Ching-Tai N

    Recurrent patterns of DNA copy number alterations in tumors reflect metabolic selection pressures.

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    Copy number alteration (CNA) profiling of human tumors has revealed recurrent patterns of DNA amplifications and deletions across diverse cancer types. These patterns are suggestive of conserved selection pressures during tumor evolution but cannot be fully explained by known oncogenes and tumor suppressor genes. Using a pan-cancer analysis of CNA data from patient tumors and experimental systems, here we show that principal component analysis-defined CNA signatures are predictive of glycolytic phenotypes, including 18F-fluorodeoxy-glucose (FDG) avidity of patient tumors, and increased proliferation. The primary CNA signature is enriched for p53 mutations and is associated with glycolysis through coordinate amplification of glycolytic genes and other cancer-linked metabolic enzymes. A pan-cancer and cross-species comparison of CNAs highlighted 26 consistently altered DNA regions, containing 11 enzymes in the glycolysis pathway in addition to known cancer-driving genes. Furthermore, exogenous expression of hexokinase and enolase enzymes in an experimental immortalization system altered the subsequent copy number status of the corresponding endogenous loci, supporting the hypothesis that these metabolic genes act as drivers within the conserved CNA amplification regions. Taken together, these results demonstrate that metabolic stress acts as a selective pressure underlying the recurrent CNAs observed in human tumors, and further cast genomic instability as an enabling event in tumorigenesis and metabolic evolution

    Risk factors for hospital admission with RSV bronchiolitis in England: a population-based birth cohort study.

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    OBJECTIVE: To examine the timing and duration of RSV bronchiolitis hospital admission among term and preterm infants in England and to identify risk factors for bronchiolitis admission. DESIGN: A population-based birth cohort with follow-up to age 1 year, using the Hospital Episode Statistics database. SETTING: 71 hospitals across England. PARTICIPANTS: We identified 296618 individual birth records from 2007/08 and linked to subsequent hospital admission records during the first year of life. RESULTS: In our cohort there were 7189 hospital admissions with a diagnosis of bronchiolitis, 24.2 admissions per 1000 infants under 1 year (95%CI 23.7-24.8), of which 15% (1050/7189) were born preterm (47.3 bronchiolitis admissions per 1000 preterm infants (95% CI 44.4-50.2)). The peak age group for bronchiolitis admissions was infants aged 1 month and the median was age 120 days (IQR = 61-209 days). The median length of stay was 1 day (IQR = 0-3). The relative risk (RR) of a bronchiolitis admission was higher among infants with known risk factors for severe RSV infection, including those born preterm (RR = 1.9, 95% CI 1.8-2.0) compared with infants born at term. Other conditions also significantly increased risk of bronchiolitis admission, including Down's syndrome (RR = 2.5, 95% CI 1.7-3.7) and cerebral palsy (RR = 2.4, 95% CI 1.5-4.0). CONCLUSIONS: Most (85%) of the infants who are admitted to hospital with bronchiolitis in England are born at term, with no known predisposing risk factors for severe RSV infection, although risk of admission is higher in known risk groups. The early age of bronchiolitis admissions has important implications for the potential impact and timing of future active and passive immunisations. More research is needed to explain why babies born with Down's syndrome and cerebral palsy are also at higher risk of hospital admission with RSV bronchiolitis
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