30,987 research outputs found

    CONVEX-BODIES, ECONOMIC CAP COVERINGS, RANDOM POLYTOPES

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    Let K be a convex compact body with nonempty interior in the d-dimensional Euclidean space Rd and let x1, …, xn be random points in K, independently and uniformly distributed. Define Kn = conv {x1, …, xn}. Our main concern in this paper will be the behaviour of the deviation of vol Kn from vol K as a function of n, more precisely, the expectation of the random variable vol (K\Kn). We denote this expectation by E (K, n)

    RPNet: an End-to-End Network for Relative Camera Pose Estimation

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    This paper addresses the task of relative camera pose estimation from raw image pixels, by means of deep neural networks. The proposed RPNet network takes pairs of images as input and directly infers the relative poses, without the need of camera intrinsic/extrinsic. While state-of-the-art systems based on SIFT + RANSAC, are able to recover the translation vector only up to scale, RPNet is trained to produce the full translation vector, in an end-to-end way. Experimental results on the Cambridge Landmark dataset show very promising results regarding the recovery of the full translation vector. They also show that RPNet produces more accurate and more stable results than traditional approaches, especially for hard images (repetitive textures, textureless images, etc). To the best of our knowledge, RPNet is the first attempt to recover full translation vectors in relative pose estimation

    Depression and anxiety in multisomatoform disorder: Prevalence and clinical predictors in primary care

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    Objective. Multisomatoform disorder (MSD) is characterised by ≥3 medically inexplicable, troublesome physical symptoms, together with a ≥2-year history of somatisation. The aim of this study was to evaluate the prevalence of depressive and anxiety disorders in a South African sample MSD, and to compare demographic and clinical outcomes in those patients with and without co-morbidity. Methods. Fifty-one adult outpatients with MSD were recruited from primary care clinics in the Cape Town metropole. Participants were assessed for the presence of co-morbid depressive and anxiety disorders using the Mini Neuropsychiatric Interview-Plus (MINI-Plus). Outcomes included somatic symptom severity, disability, reported sick days and health care visits, pain experience, patient satisfaction with health services, and clinician-experienced difficulty. Results. A current co-morbid depressive disorder was present in 29.4% (N=15) of patients, and a current co-morbid anxiety disorder in 52.9% (N=27). MSD patients with a co-morbid depressive disorder (current or lifetime) had significantly higher physical symptom counts, greater functional impairment, higher unemployment rates, more clinicianreported difficulties, and more dissatisfaction with health care services than those without the disorder. A larger number of co-morbid disorders was associated with greater overall disability. Conclusion. High rates of co-morbid depressive and anxiety disorders were present in a South African sample of primary care patients with MSD. Not all patients had co-morbidity, which is consistent with the view that MSD should be viewed as an independent disorder. However, co-morbid depressive disorders were associated with increased symptom severity and functional impairment, consistent with previous reports from developing countries, emphasising the importance of comorbidity in MSD.South African Medical Journal Vol. 98 (6) 2008 pp. 473-47

    Medicine’s inconvenient truth: The placebo/nocebo effect

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    Placebo and nocebo effects are often regarded by clinicians as either a quaint reminiscence from the pre-therapeutic era, or simply as a technique for establishing the efficacy of therapeutic interventions within the locus of evidence-based practice. However, neither of these explanations sufficiently account for their complexity or their persistence and impact in clinical medicine. Placebo and nocebo effects are embedded in the very fabric of therapeutic relationships and are both a manifestation and outcome of the rituals that characterise clinical practice. They are also a stark reminder of the many personal and environmental factors, including the attitudes, beliefs and expectations of both doctor and patient, that shape the outcomes of health professional-patient interactions. We describe how recent biological and neuropsychiatric data have clarified the operation of placebo and nocebo effects in clinical practice – demonstrating the ability of the therapeutic context to modulate endogenous biological processes in a targeted manner. This, in turn, illustrates the potent philosophical and sociocultural aspects of medical praxis. Keywords: placebo; nocebo; context effect; medical therapeutics; medical practice; medical ethic

    Medicine’s inconvenient truth: The placebo/nocebo effect

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    Placebo and nocebo effects are often regarded by clinicians as either a quaint reminiscence from the pre-therapeutic era, or simply as a technique for establishing the efficacy of therapeutic interventions within the locus of evidence-based practice. However, neither of these explanations sufficiently account for their complexity or their persistence and impact in clinical medicine. Placebo and nocebo effects are embedded in the very fabric of therapeutic relationships and are both a manifestation and outcome of the rituals that characterise clinical practice. They are also a stark reminder of the many personal and environmental factors, including the attitudes, beliefs and expectations of both doctor and patient, that shape the outcomes of health professional-patient interactions. We describe how recent biological and neuropsychiatric data have clarified the operation of placebo and nocebo effects in clinical practice – demonstrating the ability of the therapeutic context to modulate endogenous biological processes in a targeted manner. This, in turn, illustrates the potent philosophical and sociocultural aspects of medical praxis. Keywords: placebo; nocebo; context effect; medical therapeutics; medical practice; medical ethic

    Does environment affect the star formation histories of early-type galaxies?

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    Differences in the stellar populations of galaxies can be used to quantify the effect of environment on the star formation history. We target a sample of early-type galaxies from the Sloan Digital Sky Survey in two different environmental regimes: close pairs and a general sample where environment is measured by the mass of their host dark matter halo. We apply a blind source separation technique based on principal component analysis, from which we define two parameters that correlate, respectively, with the average stellar age (eta) and with the presence of recent star formation (zeta) from the spectral energy distribution of the galaxy. We find that environment leaves a second order imprint on the spectra, whereas local properties - such as internal velocity dispersion - obey a much stronger correlation with the stellar age distribution.Comment: 5 pages, 2 figures. Proceedings of JENAM 2010, Symposium 2: "Environment and the formation of galaxies: 30 years later

    Product recognition in store shelves as a sub-graph isomorphism problem

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    The arrangement of products in store shelves is carefully planned to maximize sales and keep customers happy. However, verifying compliance of real shelves to the ideal layout is a costly task routinely performed by the store personnel. In this paper, we propose a computer vision pipeline to recognize products on shelves and verify compliance to the planned layout. We deploy local invariant features together with a novel formulation of the product recognition problem as a sub-graph isomorphism between the items appearing in the given image and the ideal layout. This allows for auto-localizing the given image within the aisle or store and improving recognition dramatically.Comment: Slightly extended version of the paper accepted at ICIAP 2017. More information @project_page --> http://vision.disi.unibo.it/index.php?option=com_content&view=article&id=111&catid=7

    The Conditional Lucas & Kanade Algorithm

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    The Lucas & Kanade (LK) algorithm is the method of choice for efficient dense image and object alignment. The approach is efficient as it attempts to model the connection between appearance and geometric displacement through a linear relationship that assumes independence across pixel coordinates. A drawback of the approach, however, is its generative nature. Specifically, its performance is tightly coupled with how well the linear model can synthesize appearance from geometric displacement, even though the alignment task itself is associated with the inverse problem. In this paper, we present a new approach, referred to as the Conditional LK algorithm, which: (i) directly learns linear models that predict geometric displacement as a function of appearance, and (ii) employs a novel strategy for ensuring that the generative pixel independence assumption can still be taken advantage of. We demonstrate that our approach exhibits superior performance to classical generative forms of the LK algorithm. Furthermore, we demonstrate its comparable performance to state-of-the-art methods such as the Supervised Descent Method with substantially less training examples, as well as the unique ability to "swap" geometric warp functions without having to retrain from scratch. Finally, from a theoretical perspective, our approach hints at possible redundancies that exist in current state-of-the-art methods for alignment that could be leveraged in vision systems of the future.Comment: 17 pages, 11 figure

    Labrador retrievers under primary veterinary care in the UK: demography, mortality and disorders

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    Abstract Background Labrador retrievers are reportedly predisposed to many disorders but accurate prevalence information relating to the general population are lacking. This study aimed to describe demography, mortality and commonly recorded diseases in Labrador retrievers under UK veterinary care. Methods The VetCompass™ programme collects electronic patient record data on dogs attending UK primary-care veterinary practices. Demographic analysis covered all33,320 Labrador retrievers in the VetCompass™ database under veterinary care during 2013 while disorder and mortality data were extracted from a random sample of 2074 (6.2%) of these dogs. Results Of the Labrador retrievers with information available, 15,427 (46.4%) were female and 15,252 (53.6%) were male. Females were more likely to be neutered than males (59.7% versus 54.8%, P <  0.001). The overall mean adult bodyweight was 33.0 kg (SD 6.1). Adult males were heavier (35.2 kg, SD 5.9 kg) than adult females (30.4 kg, SD 5.2 kg) (P <  0.001). The median longevity of Labrador retrievers overall was 12.0 years (IQR 9.9–13.8, range 0.0–16.0). The most common recorded colours were black (44.6%), yellow (27.8%) and liver/chocolate (reported from hereon as chocolate) (23.8%). The median longevity of non-chocolate coloured dogs (n = 139, 12.1 years, IQR 10.2–13.9, range 0.0–16.0) was longer than for chocolate coloured animals (n = 34, 10.7 years, IQR 9.0–12.4, range 3.8–15.5) (P = 0.028). Of a random sample of 2074 (6.2%) Labrador retrievers under care in 2013 that had full disorder data extracted, 1277 (61.6%) had at least one disorder recorded. The total number of dogs who died at any date during the study was 176. The most prevalent disorders recorded were otitis externa (n = 215, prevalence 10.4%, 95% CI: 9.1–11.8), overweight/obesity (183, 8.8%, 95% CI: 7.6–10.1) and degenerative joint disease (115, 5.5%, 95% CI: 4.6–6.6). Overweight/obesity was not statistically significantly associated with neutering in females (8.3% of entire versus 12.5% of neutered, P = 0.065) but was associated with neutering in males (4.1% of entire versus 11.4% of neutered, P < 0.001). The prevalence of otitis externa in black dogs was 12.8%, in yellow dogs it was 17.0% but, in chocolate dogs, it rose to 23.4% (P < 0.001). Similarly, the prevalence of pyo-traumatic dermatitis in black dogs was 1.1%, in yellow dogs it was 1.6% but in chocolate dogs it rose to 4.0% (P = 0.011). Conclusions The current study assists prioritisation of health issues within Labrador retrievers. The most common disorders were overweight/obesity, otitis externa and degenerative joint disease. Males were significantly heavier females. These results can alert prospective owners to potential health issues and inform breed-specific wellness checks
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