325 research outputs found

    SynthETIC: an individual insurance claim simulator with feature control

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    Recent years have seen rapid increase in the application of machine learning to insurance loss reserving. They yield most value when applied to large data sets, such as individual claims, or large claim triangles. In short, they are likely to be useful in the analysis of any data set whose volume is sufficient to obscure a naked-eye view of its features. Unfortunately, such large data sets are in short supply in the actuarial literature. Accordingly, one needs to turn to synthetic data. Although the ultimate objective of these methods is application to real data, the use of synthetic data containing features commonly observed in real data is also to be encouraged. While there are a number of claims simulators in existence, each valuable within its own context, the inclusion of a number of desirable (but complicated) data features requires further development. Accordingly, in this paper we review those desirable features, and propose a new simulator of individual claim experience called SynthETIC. Our simulator is publicly available, open source, and fills a gap in the non-life actuarial toolkit. The simulator specifically allows for desirable (but optionally complicated) data features typically occurring in practice, such as variations in rates of settlements and development patterns; as with superimposed inflation, and various discontinuities, and also enables various dependencies between variables. The user has full control of the mechanics of the evolution of an individual claim. As a result, the complexity of the data set generated (meaning the level of difficulty of analysis) may be dialled anywhere from extremely simple to extremely complex

    Three patients with homozygous familial hypercholesterolemia: Genomic sequencing and kindred analysis.

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    BackgroundHomozygous Familial Hypercholesterolemia (HoFH) is an inherited recessive condition associated with extremely high levels of low-density lipoprotein (LDL) cholesterol in affected individuals. It is usually caused by homozygous or compound heterozygous functional mutations in the LDL receptor (LDLR). A number of mutations causing FH have been reported in literature and such genetic heterogeneity presents great challenges for disease diagnosis.ObjectiveWe aim to determine the likely genetic defects responsible for three cases of pediatric HoFH in two kindreds.MethodsWe applied whole exome sequencing (WES) on the two probands to determine the likely functional variants among candidate FH genes. We additionally applied 10x Genomics (10xG) Linked-Reads whole genome sequencing (WGS) on one of the kindreds to identify potentially deleterious structural variants (SVs) underlying HoFH. A PCR-based screening assay was also established to detect the LDLR structural variant in a cohort of 641 patients with elevated LDL.ResultsIn the Caucasian kindred, the FH homozygosity can be attributed to two compound heterozygous LDLR damaging variants, an exon 12 p.G592E missense mutation and a novel 3kb exon 1 deletion. By analyzing the 10xG phased data, we ascertained that this deletion allele was most likely to have originated from a Russian ancestor. In the Mexican kindred, the strikingly elevated LDL cholesterol level can be attributed to a homozygous frameshift LDLR variant p.E113fs.ConclusionsWhile the application of WES can provide a cost-effective way of identifying the genetic causes of FH, it often lacks sensitivity for detecting structural variants. Our finding of the LDLR exon 1 deletion highlights the broader utility of Linked-Read WGS in detecting SVs in the clinical setting, especially when HoFH patients remain undiagnosed after WES

    Acute Encephalopathy Associated with Influenza A Infection in Adults

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    We report acute encephalopathy associated with influenza A infection in 3 adults. We detected high cerebrospinal fluid (CSF) and plasma concentrations of CXCL8/IL-8 and CCL2/MCP-1 (CSF/plasma ratios >3), and interleukin-6, CXCL10/IP-10, but no evidence of viral neuroinvasion. Patients recovered without sequelae. Hyperactivated cytokine response may play a role in pathogenesis

    Fronto-cerebellar connectivity mediating cognitive processing speed

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    Processing speed is an important construct in understanding cognition. This study was aimed to control task specificity for understanding the neural mechanisms underlying cognitive processing speed. Forty young adult subjects performed attention tasks of two modalities (auditory and visual) and two levels of task rules (compatible and incompatible). Block-design fMRI captured BOLD signals during the tasks. Thirteen regions of interest were defined with reference to publicly available activation maps for processing speed tasks. Cognitive speed was derived from task reaction times, which yielded six sets of connectivity measures. Mixed-effect LASSO regression revealed six significant paths suggestive of a cerebello-frontal network predicting the cognitive speed. Among them, three are long range (two fronto-cerebellar, one cerebello-frontal), and three are short range (fronto-frontal, cerebello-cerebellar, and cerebello-thalamic). The long-range connections are likely to relate to cognitive control, and the short-range connections relate to rule-based stimulus-response processes. The revealed neural network suggests that automaticity, acting on the task rules and interplaying with effortful top-down attentional control, accounts for cognitive speed

    The snomipede : a parallel platform for scanning near-field photolithography.

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    Using scanning near-field lithography (SNP), it is possible to pattern molecules at surfaces with a resolution as good as 9 nm [M. Montague, R. E. Ducker, K. S. L. Chong, R. J. Manning, F. J. M. Rutten, M. C. Davies and G. J. Leggett, Langmuir 23 (13), 7328–7337 (2007)]. However, in common with other scanning probe techniques, SNP has previously been considered a serial process, hindering its use in many applications. IBM’s “Millipede” addresses this problem by utilizing an array of local probes operating in parallel. Here, we describe the construction of two instruments (Snomipedes) that integrate near-field optical methods into the parallel probe paradigm and promise the integration of top–down and bottom–up fabrication methods over macroscopic areas. Both are capable of performing near-field lithography with 16 probes in parallel spanning approximately 2 mm. The instruments can work in both ambient and liquid environments, key to many applications in nanobiology. In both, separate control of writing is possible for each probe. We demonstrate the deprotection of self-assembled monolayers of alkylsilanes with photocleavable protecting groups and subsequent growth of nanostructured polymer brushes from these nanopatterned surfaces by atom-transfer radical polymerization

    Autistic Disorders and Schizophrenia: Related or Remote? An Anatomical Likelihood Estimation

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    Shared genetic and environmental risk factors have been identified for autistic spectrum disorders (ASD) and schizophrenia. Social interaction, communication, emotion processing, sensorimotor gating and executive function are disrupted in both, stimulating debate about whether these are related conditions. Brain imaging studies constitute an informative and expanding resource to determine whether brain structural phenotype of these disorders is distinct or overlapping. We aimed to synthesize existing datasets characterizing ASD and schizophrenia within a common framework, to quantify their structural similarities. In a novel modification of Anatomical Likelihood Estimation (ALE), 313 foci were extracted from 25 voxel-based studies comprising 660 participants (308 ASD, 352 first-episode schizophrenia) and 801 controls. The results revealed that, compared to controls, lower grey matter volumes within limbic-striato-thalamic circuitry were common to ASD and schizophrenia. Unique features of each disorder included lower grey matter volume in amygdala, caudate, frontal and medial gyrus for schizophrenia and putamen for autism. Thus, in terms of brain volumetrics, ASD and schizophrenia have a clear degree of overlap that may reflect shared etiological mechanisms. However, the distinctive neuroanatomy also mapped in each condition raises the question about how this is arrived in the context of common etiological pressures

    Rates of Potentially Inappropriate Dosing of Direct-Acting Oral Anticoagulants and Associations With Geriatric Conditions Among Older Patients With Atrial Fibrillation: The SAGE-AF Study

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    Background: Direct-acting oral anticoagulant (DOAC) dosing guidelines for atrial fibrillation recommend dose alteration based on age, renal function, body weight, and drug-drug interactions. There is paucity of data describing the frequency and factors associated with prescription of potentially inappropriate doses. Methods and Results: In the ongoing SAGE-AF (Systematic Assessment of Geriatric Elements in Atrial Fibrillation) study, we performed geriatric assessments (frailty, cognitive impairment, sensory impairments, social isolation, and depression) for participants with atrial fibrillation (age \u3e /=65 years, CHA2DS2VASc \u3e /=2, no anticoagulant contraindications). We developed an algorithm to analyze DOAC dose appropriateness accounting for drug-drug interactions, age, renal function, and body weight. We also examined whether geriatric impairments were related to inappropriate dosing. Of 1064 patients prescribed anticoagulants, 460 received a DOAC. Participants were aged 74+/-7 years, 49% were women, and 82% were white. A quarter (23%; n=105) of participants received inappropriate DOAC dose, of whom 82 (78%) were underdosed and 23 (22%) were overdosed. Among participants receiving an inappropriate dose, 12 (11%) were identified using the drug-drug interactions criteria and would have otherwise been misclassified. In multivariable regression analyses, older age, higher CHA2DS2VASc score, and history of renal failure were associated with inappropriate DOAC dosing (P \u3c 0.05). Geriatric conditions were not associated with inappropriate dosing. Conclusions: In this cohort, over 20% of older patients with atrial fibrillation treated with DOACs were prescribed an inappropriate dose, with most being underdosed. Drug-drug interactions were common. Factors that influence prescription of guideline-nonadherent doses may be perception of higher bleeding risk or presence of renal failure in addition to lack of familiarity with dosing guidelines
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